Gmail not working?

I’m deeply confused:
I can’t send transactional mails to gmail adresses: I’m using mailgun for both bulk and transactional emails. The bulk email works fine, newsletters are received. But sign in emails and staff invitations to gmails don’t work. I’m not aware of any other email providers with the same issues. The hell?

I assume you’re self-hosting? What do your mailgun logs say, if anything? (Do they show that mailgun received the emails and delivery failed, or do they show it not receiving them?)

Ah nevermind, I didn’t realize the “support email” under the portal settings was gonna be the from address in these mails, leading to an email acceptance clusterfuck

Please make sure that the content and format of your transactional emails should be according to your Gmail guidelines.