Hey there,
We have been using Chrome's extension 'Salesforce' to log emails from Gmail to Salesforce. For last 3 days, we are facing the error 'Hmm. The email server is unavailable. Try again later.' Attaching screenshots for reference.
@POONAM SINGH. Seconding @Lauren McCaffrey question also if you had found a solution. My org. is also having issues with this and we have had an open ticket with no response with Salesforce for 4+ months now.