DNS problem: SERVFAIL looking up CAA

That's my theory, but I can't tell you for sure.

I believe that this is a corroboration of the issue: git.shifudao.com | DNSViz

Sign in · JiHu GitLab The server responded with no OPT record, rather than with RCODE FORMERR. (121.12.104.109, 121.12.104.110, 183.2.194.173, 183.2.194.174, 218.66.171.173, 218.66.171.174, 218.98.111.173, 218.98.111.174, UDP_0_EDNS0_32768_4096)

At least, it has been an issue before: DNS problem: SERVFAIL looking up CAA for www.imolaenergy.hu - #11 by MitchellK

I see you've removed the CAA record now, does that help things for you?