Certificate cache on iOS with sending mail

So I generated a new certificate for dovecot, and ever since I have this weird problem that my iPhone can still receive mail but cannot send using that mailserver. Same for my iMac.

My laptop works fine still and can do both. Local issue you would say right.

I'm wondering if there is any cache for a certificate or something, my maillog shows up something like 10 bytes read, -1. So it returns an error. I deleted the accounts and created them again, still no go.

Anyone had anything similar before?

Sent from my iPhone