[iCloud Mail] custom domain doesn't work

Hello,

I have 2 custom domains that I used with iCloud Mail. I set them up and everything worked perfectly. I had a few e-mail addresses created in them and added rules to auto sort them. I then saw the catch-all domain option and enabled it and I think I deleted some of the mail addresses I had because I already have catch-all enabled. After some time I get a notification saying I can't send or receive mails from one of my domains and that I need to reverify it. I need to set up SPF and MX records and all that. I check again and it looks like apple wants my "apple-domain=" TXT record to be something else this time. Weird that it randomly changed but okay. I change it and make sure that everything else is correct. Then I wait a few days and try to reverify but apparently I need to check my SPF record. Keep in mind I had done this all before and it worked perfectly and I haven't changed it.

What's even weirder is that I tested it and I can send and receive mails from that domain. Catch-all addresses work too. I can only not send from or receive to spam@domain.com. Which was an old e-mail address that I deleted after I enabled catch-all. My second domain is the same but I didn't get asked to reverify it. spam@otherdomain.com doesn't work either.

After trying a few different stuff a few times, I decided to just remove my domains from iCloud Mail and connect them again from the beginning. I am back where I was: I can't verify the domain that I was asked to reverify (I get asked to check my SPF record which I have done many times) and spam@otherdomain.com doesn't work.

At this point I'm pretty annoyed because Apple does not have an official support for iCloud Mail. Only option on support website is to call which will never work in my case because the problem is complex. And I doubt I can even explain it to the operator.

Did anyone here experience something similar? I would gladly get any help you can offer. But please keep in mind: I have set up 2 custom domains before that worked. Please do not recommend me to set it up again or check SPF or something. I suspect it has something to do with me setting up catch-all domain and then deleting an e-mail address that I had.

Best Regards