OK, so in the above domain example I posted I ran the following after a while:
# grep .well-known/acme-challenge/uOlojY6V-O5JLkbabQduryEmWlCdge21TXxDuaFPL-c /var/log/apache2/*_log
/var/log/apache2/access_log:3.16.151.34 - - [18/Apr/2024:17:51:54 +0200] "GET /.well-known/acme-challenge/uOlojY6V-O5JLkbabQduryEmWlCdge21TXxDuaFPL-c HTTP/1.1" 200 87
/var/log/apache2/access_log:54.244.62.108 - - [18/Apr/2024:17:51:54 +0200] "GET /.well-known/acme-challenge/uOlojY6V-O5JLkbabQduryEmWlCdge21TXxDuaFPL-c HTTP/1.1" 200 87
/var/log/apache2/access_log:23.178.112.101 - - [18/Apr/2024:17:51:54 +0200] "GET /.well-known/acme-challenge/uOlojY6V-O5JLkbabQduryEmWlCdge21TXxDuaFPL-c HTTP/1.1" 200 87
/var/log/apache2/access_log:184.105.99.36 - - [18/Apr/2024:18:08:13 +0200] "GET /.well-known/acme-challenge/uOlojY6V-O5JLkbabQduryEmWlCdge21TXxDuaFPL-c: HTTP/1.1" 404 37
As you can see I got the fourth connection (the fifth one didn't come up). However, it came way too late. At that time I think the certbot had already finished (that's why I see a 404 there).
184.105.99.36 is from Seattle, and I shouldn't have any issues on my side accepting connections from there.
Why did that connection happen so late?
[EDIT] Also, if I get the following message I guess it's because I'm being rate limited?
An unexpected error occurred:
There were too many requests of a given type :: Service busy; retry later.
If so, after how long can I retry?