Okay, something is weird. I have Outlook.com email with custom domain (previously Windows Live Domains). These kind of accounts had problems with Nylas since forever (see my old GitHub issue - https://github.com/nylas/nylas-mail/issues/859). I have tried adding it to new Nylas app with Office 365/custom IMAP with no success.

The weird thing is, in last 15 minutes someone from USA - AWS instance, 35.167.235.231 - tried to connect to my account. This app is said to sync locally, right? But I see no attempts from my IP in Outlook.com panel, but about ten from AWS. All of these started when I installed Nylas and tried to configure it; remaining logins logged by Microsoft are 100% by me (web client, iPhone Mail.app). WTF?

edit: https://a.pomf.cat/gxhabs.png

2nd edit: According to https://github.com/nylas/nylas-mail/issues/3405#issuecomment... someone else is unable to connect with GMail because of Nylas servers throwing HTTP 502. Does it sync locally or through Nylas' AWS instances? Is this why I can't configure my account with IMAP?

It syncs locally by also can make server requests for things like snoozing/reminders/send later.

Not sure on the exact details of your account but if you send a quick note to support@nylas.come one of our engineers can look into it.

Is it possible to turn it off? I don't want these, but looks like I have effectively given you password to my email account. Can you remove it from your database?

Yep just email that address and we'll take care of it.

I've been looking forward to trying this out, no good mail clients on Linux

Sorry-- our servers are getting hammered right now. Team is working on a fix.

I just retried several times until it got through. Syncing accounts right now. Only problem is I can't find the "File, Edit..." menu on Ubuntu Budgie 17.04, but rest of the functionality works great so far.

Edit: well, I'm low on coffee today. Just press Alt key to show the menu! Not a nylas problem :)