When the final poll (`_link_cert_retry` at 29) returns, the status
is never checked again. So even a `valid` status goes unnoticed.
It's a pre-test loop after all.
Co-authored-by: Oliver Behnke <oliver.behnke@aei.mpg.de>
Fixes the following error when debugging is enabled:
[Sat Feb 21 04:00:22 CET 2026] Here is the curl dump log:
[Sat Feb 21 04:00:22 CET 2026] * URL rejected: Port number was not a decimal number between 0 and 65535
* closing connection #-1
IPv6 addresses in URLs need to be written like this:
http://[2001:43:5::250]