Trusting SSL certificate for mail on iPadOS 14

[arethinn]

I have mail set up on eristic.net. It's shared hosting, so the underlying "real" server name is actually a subdomain of asoshared.com. Thus, whenever asoshared.com's security certificates are renewed (as just happened a few days ago), mail apps complain about the name mismatch and I have to approve an exception to trust the certificate anyway. No big deal, so long as I'm able to do that; it was no problem in Thunderbird. It had also previously been working in the Mail app on my iPad, so I must have been able to do similar exceptions there as well. I thought there should be place I could just click "Trust" on the warning, but this time, for the life of me I can't figure out how to trust the certificate. This sort of thing and this seem like varying amounts of "maybe not even the right solution" plus "seems like more work than I should have to go through" plus "I might not be able to accomplish all that anyway" (there is not actually any certificate for eristic.net, and I'm not sure I could create one). I wondered if maybe this had changed between iPadOS 13 and 14, but that first link even more puzzlingly gives me the idea that I should have already run into this problem in 13 (and maybe even in 12), yet I don't remember it being the case - I certainly have never done anything like the solution outlined in the first link. Does anyone have any advice?