I'm sorry for having opened the thread and maybe had the wrong debug method.
I solved the problem.
I forgot I set up a HTTP challenge in the begginning that pointed to the internal OpnSense webserver, because using the HAproxy integration things never worked right. Bu I was able to figure out what was wrong with the HAproxy configuration for the challenge and to move the challenge to HAproxy and have it working.
Tha problem was that I followed the most famous tutorial to set up the HAproxy SSL offloading and ACME Let'sEncrypt certificates and that didn't work in validating certificates, so I had the workaround to use the internal webserver for the challenge.
I had to add a rule in HAproxy, opposite to the rule that checks the challenge and redirects that traffic to the internal backend of ACME plugin to validate the certificate, and apply this opposite rule to the traffic that has to be redirected to the services backend. I think otherwise the traffic for ACME challenge was redirected to the service backends before evaluating the rule that made it redirect to the ACME webserver.
Anyway it remains a mistery that until june the challenge with internal webserver worked fine, but it doesn't matter.
I solved the problem.
I forgot I set up a HTTP challenge in the begginning that pointed to the internal OpnSense webserver, because using the HAproxy integration things never worked right. Bu I was able to figure out what was wrong with the HAproxy configuration for the challenge and to move the challenge to HAproxy and have it working.
Tha problem was that I followed the most famous tutorial to set up the HAproxy SSL offloading and ACME Let'sEncrypt certificates and that didn't work in validating certificates, so I had the workaround to use the internal webserver for the challenge.
I had to add a rule in HAproxy, opposite to the rule that checks the challenge and redirects that traffic to the internal backend of ACME plugin to validate the certificate, and apply this opposite rule to the traffic that has to be redirected to the services backend. I think otherwise the traffic for ACME challenge was redirected to the service backends before evaluating the rule that made it redirect to the ACME webserver.
Anyway it remains a mistery that until june the challenge with internal webserver worked fine, but it doesn't matter.