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'Unable to connect to mailbox' on Office365-hosted mailboxes
Answer ID 9913   |   Last Review Date 01/27/2019

Why do we receive the "Unable to connect to mailbox" error when the Techmail utility attempts to connect to our Office365 mailbox?


Office365-hosted mailboxes
Oracle B2C Service, All versions


The 'Unable to connect to mailbox' notification is encountered when the Techmail-S utility attempts to connect to the mailbox.


Please find below the most common causes for the error message:

1. Verify that the POP server configuration is correct and perform the change if needed. Example Office365 POP server: ''.

2. Verify that the SSL method used for this mailbox is 'Use POP3 SSL port' and perform the change if needed. Techmail can connect to an Office365 mailbox only on port 995. Connections performed on ports 110 (SSL method disabled or STLS method) will generate connectivity errors.

3. Verify that the POP account and password are correct and re-type both in the mailbox configuration page in order to make sure that the utility uses the correct credentials when connecting.

4. Verify that the POP account password is not longer than 20 characters.

5. If the above steps are completed and Techmail still fails to connect to the mailbox with reason 'Unable to connect to mailbox. Server Error Message:-ERR Logon failure: unknown user name or bad password', please check the Office365 mailbox from Microsoft's end and make sure that the Office365 account has E-mail capability:

- Please use and log into the Office365 account;
- Once inside, go to My Account and then to Subscriptions;
- Verify that you have a working license to use Office 365's e-mail functionality.

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  Additional Information (Click the Image to expand this section for viewing.) 

- Check if you are be able to access the web-mail of your Office365 account (once logged in, click the 'Mail' button; the link should be ).

- Check within the Office365 account and make sure that Subscriptions does not show the below message:

Licenses: You don't have a license to use Office 365 with the user ID assigned to you by your work or school....

If all the above steps fail to restore the mailbox, please raise a new service request via Ask Technical Support and we will gladly assist you.