In the Mailsync Logs on the Nylas Dashboard or in the API Logs when sending an email you may see/receive the following error message:
This error message can occur when there is a configuration issue on the exchange end and prevent sending and syncing. To resolve the issue, try the following suggestions:
- Ensure the mailbox is on Office 365, not on-premise. If you are in a hybrid environment, make
sure that the mailbox is on the Office 365 side.
- Move the mailbox to another mailstore where possible. This can help resolve issues related to corrupted data or other issues with the mailbox.
- Check if it's a shared mailbox. Shared mailboxes can sometimes cause issues if the user does not have the correct permissions or if there are issues with syncing the mailbox.
- For new users, ensure that the mailbox has been provisioned and has something in it. This can help avoid issues related to a missing mailbox or other provisioning issues.
- Check for transient infrastructure issues at Microsoft related to storage. Sometimes, this error can occur due to issues with the Microsoft infrastructure.
If none of these suggestions resolve the issue, a known solution is to provision a new
mailbox. This can help ensure that the mailbox is set up correctly and avoid any issues related to corrupted data or other issues with the mailbox.