Hello, so i run my cloudron server in my house, now i have done this before and had no issue with using an external smpt service for email delivery, i used mailgun and have never had an issue.
i used cloudflare for the domain (my dashboard is the only one that is proxyed)
mailgun for the smpt server
So, tested day i setup my SMPT outbound part and nothing seemed to be working. after sending 3 test emails mailgun says they sent. i check my inbox and they in fact send. so, a few hours later i send another test email and nothing........ i went into cloudflare removed all my TXT files ect and re did it , still nothing. i noticed after looking that unbound was yellow and not working might be the problem???
i also have the logs of my email that do have the 3 that confirmed and the rest that were rejected