How to Establish if Exchange Server is Unavailable?

This error, “ Exchange Server is unavailable”, may arise when you open MS Outlook or try to sign in to Outlook through your Exchange account credentials.

Moreover, this error can also appear when you attempt to access the Exchange account via MS Outlook in Office 365. When this error happens, you cannot access your mailbox and mailbox details will be saved on the Exchange server. Therefore, it converts into a requirement to fix this error as quickly as possible. 

Nevertheless, before proceeding through the different methods that you can use to overcome the issue, know the circumstances through which this error appears.

Causes for “Exchange Server is Unavailable”

“The connection to the Microsoft exchange server is unavailable 2013” is a common error and it’s not version-specific. There may be different reasons for the occurrence of this error.

  • Network issue.
  • Misconfigured Outlook.
  • Disabled RPC encryption.
  • An obstacle with DNS cache.
  • Read-only Outlook data files.
  • Disappeared default gateway configuration.
  • Dispute with third-party software such as antivirus.
  • Registry issues.
  • Outlook or Exchange server is not accessible.

Manually fix the issue “Exchange Server is Unavailable” with Several Methods

In the entire blog, we are mentioning different methods to fix the issue. Follow any one of these as per your comfort.

#1. Configure LAN Setting

You can configure the Internet LAN Settings to establish the linking within the Exchange Server and the Outlook client. Follow the instruction given below:

  • Search & Open Internet options from Start Menu.
  • On the Internet Properties dialogue box, shift to the Connections tab and hit on the LAN settings option.
  • On the (LAN) Settings dialogue box, tap on the Advanced option.
  • Now, inside the Extensions section, give your mail server address and hit on OK.
  • Finally, the LAN settings are configured successfully to the mail server.

This is one of the methods to fix the issue “Exchange Server is Unavailable”.

#2. Check Conflict for Third-party Tool

Some third-party applications conflict with the Outlook application while it attempts to configure the Exchange Server account. So, it is notified to disable or remove the third-party applications from the system using the Control panel.

#3. Edit Registry 

Follow these actions to modify the Registry key and solve the Exchange connectivity issues.

  • First, press (Window+R) Key, type Regedit, and hit ‘Enter’ to open Registry Editor
  • In the left pane, navigate the following:


  • Locate ZeroConfigExchange DWORD in the right pane.
  • Right-click on the DWORD file and select Delete.

Terminate the Registry Editor window and review if the problem is fixed.

#4. Restarting All Microsoft Exchange Services

When all Microsoft Exchange Services is not running, then there could be disruption within the Exchange account and Outlook. This may also lead to Exchange Server is Unavailable.

  1. Open the Exchange Server system (on which Exchange is established).
  2. Press (Window+R), and then type services.msc and tap on OK.
  3. The Exchange Service Manager window will get started. Here explore the Microsoft Exchange Services one by one, right-click on it, and choose the Restart option for those who are not operating currently.
  4. At last, exit the window and restart the Outlook application to review if it worked.

#5. Use Microsoft Office 365 Support & Recovery Assistant

If the problem happened in Outlook 365, you can download and use Microsoft Office 365 Support & Recovery Assistant utility. After downloading, operate the tool to troubleshoot and overcome the ‘Exchange server is unavailable’ issue.

#6. Be Sure whether MS Outlook Files are Damaged

It has been seen that the Outlook file gets damaged after the upgrade and appears in corruption. You just require to go through the below-mentioned location:

C:Documents and Settings<username>Application DataMicrosoftOutlook

Review these files – Frmcache.dat, Extend.dat, Views.dat, and Outcmd.dat, and if they are still present, then you have to delete those files. It may also fix the issue “the connection to the Microsoft exchange server is unavailable 2013”. 

However, If there are any Exchange Server issues due to corrupted EDB files, we offer everyone the best professional tool i.e. EDB to PST Converter. You can use this tool to recover your Exchange Server files (.edb). 


Within the blog, we have mentioned the reason for this issue. In this blog, we describe all possible and easy methods to fix “Exchange Server is Unavailable”. I hope it will help you to fix this issue.

Also Read – Recover and Repair Corrupt Exchange Database Files

Aakshit is a blogger, writer, freelancer, publisher for the technology niche. Works as a content writer for many websites.