12 Methods to Fix Exchange Server is Unavailable Error

Updated On - November 9, 2023 by Armaan | Reading Time: 9 minutes

Nothing is perfect and Exchange Server is no exception. We know, Microsoft Exchange Server is a widely used email server that provides a platform for managing and organizing email communications for businesses and organizations. Being a service of Microsoft is technically advanced but many users still face errors while using it.

In several scenarios, Exchange Server users encounter an error that says, ‘The connection to Exchange Server is unavailable’. This error can be frustrating as it can prevent users from accessing their emails and other important information stored on the server. In this blog, we’ll discuss the causes of the “Exchange Server is Unavailable” error and provide several methods that can help users resolve the issue. Keep reading and resolve this error if you have encountered it.

Causes of Exchange Server is Unavailable Error

The connection to Exchange Server is unavailable error can be caused by a number of reasons, including:

• Network Issues: The server may be unavailable due to network problems, such as DNS issues, connectivity problems, or firewall restrictions. Also, pay attention to your LAN settings.
• Server Maintenance: The server may be down for maintenance or upgrades, which can cause it to become temporarily unavailable.
• Software Issues: The Exchange Server may encounter software errors that can cause it to become unavailable, such as errors in the server software or a corrupt database.
• Hardware Issues: The server hardware may be faulty or damaged, which can cause the server to become unavailable.
• Conflict with Alien Application: When a third-party alien application doesn’t synchronize with your setup, chances of such type of server and client error increase.
• Add-ons in Outlook: Several add-ons in Outlook, despite enhancing work-experience and providing a helpful hand, creates issues. We mostly use add-ons for grammar and other checks but we unknowingly get in the touch with faulty ones and they cause such Exchange Server errors.

Verified Solutions to Fix Exchange Server is Unavailable Error

Here are some manual methods/workarounds that can help you to resolve the Exchange Server is Unavailable error. Try them and check which one suits you.

Method 1: Check Network Connectivity

The first step is to check the network connectivity between your computer and the Exchange Server. Check that your computer is connected to the network and that there are no connectivity issues. Also, ensure that your computer has a valid IP address and that it can communicate with the Exchange Server. If there are any connectivity issues, contact your network administrator. Must cross-check for the Exchange Server maintenance downtime updates.

Method 2: Restart the Exchange Server

The server may become unavailable due to a temporary issue or maintenance. In such cases, restarting the Exchange Server may resolve the issue. To do this, follow these steps:

• Log in to the Exchange Server as an administrator.
• Open the Services window by pressing Windows + R and typing “services.msc” in the Run dialog box.
• Locate the Microsoft Exchange Information Store service and right-click on it.
• Select the Restart option from the context menu.

Method 3: Check Exchange Services

Another reason for the Exchange Server is Unavailable error could be that some of the Exchange services are not running. To check the status of the Exchange services, follow these steps:

• Log in to the Exchange Server as an administrator.
• Open the Services window by pressing Windows + R and typing “services.msc” in the Run dialog box.
• Locate the Microsoft Exchange Information Store service and ensure that it is running.
• Check the status of other Exchange services, such as Microsoft Exchange Transport, Microsoft Exchange Mailbox Assistants, and Microsoft Exchange Active Directory Topology services. Ensure that these services are also running.

Method 4: Edit Registry Value

In several scenarios, it has been noticed that an incorrect Registry value was behind the “Exchange Server is Unavailable” Error.

So, change the registry value by following the steps:

• To reach the registry editor, press Windows with R.
• Then type “Regedit” and click OK.
• A permission box will open; permit by clicking yes.
• “Registry Editor Window” will open; locate “HKEY_Current_User” >> Software.
• Follow the steps: Microsoft >> Office >> Outlook >> RPC.
• After that, click on the File tab and then Edit >> New >> DWORD.
• Insert the following text: DefConnectsOpts >> Enter.
• Make a right-click on DefConnectsOpts >> Modify.
• Finally, here, you must enter the value 0 and click OK.

Method 5: Check Firewall and Antivirus Settings

Firewall or antivirus settings can sometimes block the Exchange Server, causing it to become unavailable. Check the firewall settings to ensure that the Exchange Server ports are open. Also, check the antivirus settings to ensure that the Exchange Server files are not being quarantined or blocked.

Method 6: Check DNS Settings and Flush DNS

• DNS settings can also cause the Exchange Server is Unavailable error. Ensure that the Exchange Server is listed in the DNS server and that the DNS settings are correct. Go to the start menu and type “cmd.”
• Run it as “Run as administrator.” For this, make a right-click.
• Next, the command prompt window will open.
• Type “ipconfig/flushdns.” (see the screenshot for clarity).
• Close the command prompt and check if the error is resolved.

Method 7: Reinstall Exchange Server

If none of the above methods work, you may need to reinstall Exchange Server. Before doing so, ensure that you have a backup of all your Exchange data. To reinstall Exchange Server, follow these steps:

• Log in to the Exchange Server as an administrator.
• Uninstall the Exchange Server software from the Control Panel.
• Restart the server.
• Reinstall the Exchange Server software.
• Restore your Exchange data from the backup.

So, these are the manual methods, that you can use to resolve the Exchange server is unavailable error. Apart from this, you can use an automated tool recommended for exchange administrators by Microsoft MVPs.

Method 8: Remove the Old Outlook Profile and Create a New Outlook Profile

• Go to the Control Panel and select Mail (Microsoft Outlook).
• Under the Profile Section, select the Show Profiles.
• Select the Profile and click on the Remove.
• By following the above steps, you can simply remove the old Outlook profile. Now follow the below-given steps to create a new profile:
• Select Mail (Microsoft Outlook) from Control Panel >> Show Profile.
• Click on the Add… option and then OK.
• Give a name to the new profile and click OK.
• Enter the credentials of the email account and click Next.
• Check “Change Account Settings” and Next.

A new Outlook Profile will be created; now check if you have fixed the “Exchange Server Unavailable” error.

Method 9: Cross-check the Outlook Data File Permission Level

In some cases, it is found that due to the “read-only” permission level, users also ace the issue. Cross-check it:

• Go to the drive location.
  “C:\Users\username\AppData>Local>\Microsoft Outlook.”
• Select the Outlook folder >> Properties.
• Now, check if “Read-only” is checked or not. If checked, then de-select and uncheck and click OK.

Method 10: Start Microsoft Exchange Attendant

If the problem is in Server side, then you must check for the M.E.S. Attendant. Follow below steps to start M.E.S. Attendant service:

• In the search box type “Windows PowerShell” (Run as Administrator).
• In the Service Window >> Details pane >> locate Microsoft Exchange Attendant Service.
• Start it.

Method 11: Repair Corrupt Exchange Database

If the Exchange database is corrupt, it can cause the server to become unavailable. To repair a corrupt Exchange database, follow these steps:

• Log in to the Exchange Server as an administrator.
• Open the Exchange Management Shell.
• Run the following command to verify the integrity of the Exchange database: ESEUTIL /MH “C:\Program Files\Microsoft\Exchange Server\V15\Mailbox\Mailbox Database\Mailbox Database.edb”
• If the database is found to be corrupt, run the following command to repair it: ESEUTIL /P “C:\Program Files\Microsoft\Exchange Server\V15\Mailbox\Mailbox Database\Mailbox Database.edb”
• After repairing the database, run the following command to defragment it: ESEUTIL /D “C:\Program Files\Microsoft\Exchange Server\V15\Mail

Apart from this manual method, you can use an automated tool named Regain EDB to PST converter tool to repair corrupt Exchange database.

If still fail to fix the “Exchange Server is Unavailable” error then you must go with a professional tool. Professional solutions are developed to resolve issues in an expert manner. Now, let’s move toward it:

Method 12: Use a Professional Tool to Fix All Exchange Server Issues

To provide a one-stop solution for the Exchange Server and its file format (EDB), Regain Software has developed an advanced utility. Regain EDB to PST Converter is a highly advanced software that allows users to convert EDB files from Microsoft Exchange Server to PST files for Microsoft Outlook.

• This tool is also capable of recovering data from inaccessible or corrupt Exchange Server databases, including emails, contacts, calendars, tasks, notes, and more.
• One of the benefits of using this software is that it can recover EDB data without needing to access the Exchange Server directly. This can be useful in situations where the server is unavailable or inaccessible due to technical issues or maintenance.
• Software also provides a user-friendly interface and offers various features, including selective data recovery, preview of recoverable items, support for multiple EDB files, and more.
• Additionally, the software is compatible with all versions of Exchange Server and Microsoft Outlook, making it a versatile tool for recovering data from Exchange Server databases.

So, if all above mentioned manual workarounds didn’t work for you then you should move toward repairing the EDB file where you get options to save data in other prominent file formats. Overall, the Regain EDB to PST converter can be a helpful tool for users experiencing the Exchange Server is Unavailable error and looking for a reliable solution to recover their Exchange EDB data.

Free Download100% Secure Buy NowPrice: $89

An Automated tool to Fix all Exchange Server errors

Here are the general steps to use Regain EDB to PST Converter (aka Regain Exchange Recovery Tool) to recover data from Exchange Server’s data storage file format:

Step 1: Download and Install the Software

Download and install the Regain EDB to PST converter software from the official website.

Step 2: Launch the Software

Launch the software to proceed.

Step 3: Select the EDB File

Click the “Add EDB” button to select the EDB file that you want to recover . You can also add multiple EDB files if needed.

Step 4: Select the Destination Folder

Make selection for the resultant file format. Here, select PST and choose the destination folder where you want to save the converted PST file. You can also select specific items or folders to recover data from.

Step 5: Start the Conversion Process

Click the “Save Data” button to start the conversion process. The software will convert the EDB file to a PST file and save it to the selected destination folder.

Step 6: Save Recovered Data

Once the conversion process is complete, you can view the recovered data in the desired platform.

Step 7: Save Log Report

After the conversion process, the software will generate a log report that you can save to your computer for future reference.

Over to You!

The “Exchange Server is Unavailable” error can be caused by various issues, including network connectivity problems, software errors, hardware issues, and more. However, by following the manual methods mentioned in this blog, you can resolve the error and regain access to your Exchange Server. If none of the manual methods work, it’s recommended that you use the Regain EDB to PST converter tool. A free demo version of this advanced tool is also available to download.

Frequently Asked Questions:

Q1. Is there any chance that Exchange Server downtime is a reason behind the “Exchange Server is Unavailable” error?
Ans: When we encounter the “Exchange Server is Unavailable” error, the first thing that strikes our mind is ‘Is the Exchange Server Down’? and yes, the Exchange Server faces downtime; however, once in a blue moon. If this is the case (confirm it by visiting Microsoft’s official website news update), then wait, as there are no choices.

Q2. What registry value should I enter if changing the existing one as a workaround?
Ans: Prefer entering “0” as the registry value. See method 4 for detailed information on it.

Q3. Can I have a preview of the EDB file data before saving it into another file format?
Ans: Yes, you can see the EDB file data by expanding the folder. Before saving into any other file format, you can cross-check the data.

Q4. May I get any technical assistance from any expert to fix the “Exchange Server is Unavailable” error?
Ans: Feel free to contact Regain Software if you are not getting any resolution of your error after trying several manual methods. You can contact us through live chat, by writing to support@regainsoftware.com, or by submitting your query on the Contact Us page. You can also connect via telephone.