Google is investigating a service outage affecting Gmail users worldwide that causes issues when syncing emails with Microsoft servers via the Internet Message Access Protocol (IMAP).

On affected devices, Gmail users say they’re not receiving emails and that they’re also having issues syncing their Hotmail accounts.

Impacted customers report seeing “There was a problem while syncing this folder. Please try again later.” errors.

“I have not been able to sync my Hotmail account in the Gmail app for the last few days, my outlook account is syncing fine it is only the Gmail app that this isn’t working! I have tried everything to resolve this issue but nothing is working,” another user said.

Additional reports also point at the Gmail mobile app being the one affected by these ongoing sync issues, with desktop apps working as expected.

The company has already acknowledged the reports and says in an incident report published earlier today on the Google Workspace Status Dashboard that it started looking into this issue at 5:10 PM UTC, 20 minutes after the incident started.

“IMAP syncs with Microsoft servers experiencing failures that are causing Gmail sync issues. We currently believe the issue only affects users syncing their email from Outlook servers.” Google said.

“Customers accessing Outlook or Hotmail email accounts on Gmail application across all device platforms are unable to sync new messages.”

Google’s engineering team is still working on identifying the root cause of this ongoing outage and will share more details when additional information is available.

Update February 22, 15:38 EST: Google says that the sync problems are not caused by Gmail auth issues.

“The investigation so far from our engineering has not uncovered any issues with Gmail application authentication and we are continuing to investigate further for the root cause,” the company said in an update to the incident report.