Not able to generate a Let's Encrypt Certificat - nginx

Question

I am using Laravel Forge to manage my servers and websites. So generating SSL certificates via Let's Encrypt is also done vie Forge. Somehow one of my domains throws me an error (see attached).
This domain is running on a server which holds several other domains. The nginx configuration is exactly the same.
The application is a Laravel app running on Laravel Octane.
Error:
2022-06-13 10:41:26 URL:https://forge-certificates.laravel.com/le/1441847/1663342/ecdsa?
env=production [4653] -> "letsencrypt_script1655109686" [1] Cloning
into 'letsencrypt1655109686'... Note: switching to
'91cccc0c234e4decf0a19595fa19a6f306788032'.
You are in 'detached HEAD' state. You can look around, make
experimental changes and commit them, and you can discard any commits
you make in this state without impacting any branches by switching
back to a branch.
If you want to create a new branch to retain commits you create, you
may do so (now or later) by using -c with the switch command. Example:
git switch -c
Or undo this operation with:
git switch -
Turn off this advice by setting config variable advice.detachedHead to
false
HEAD is now at 91cccc0 ensure newline before new section in
openssl.cnf ERROR: Challenge is invalid! (returned: invalid) (result:
["type"] "http-01" ["status"] "invalid"
["error","type"] "urn:ietf:params:acme:error:connection"
["error","detail"] "111.222.333.444: Fetching
http://my-domain.de/.well-known/acme-challenge/_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw:
Timeout during connect (likely firewall problem)"
["error","status"] 400
["error"] {"type":"urn:ietf:params:acme:error:connection","detail":"111.222.333.444:
Fetching
http://my-domain.de/.well-known/acme-challenge/_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw:
Timeout during connect (likely firewall problem)","status":400}
["url"] "https://acme-v02.api.letsencrypt.org/acme/chall-v3/119151352296/awZDUg"
["token"] "_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw"
["validationRecord",0,"url"] "http://www.my-domain.de/.well-known/acme-challenge/_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw"
["validationRecord",0,"hostname"] "www.my-domain.de"
["validationRecord",0,"port"] "80"
["validationRecord",0,"addressesResolved",0] "111.222.333.444"
["validationRecord",0,"addressesResolved",1] "2a01:4f8:141:333::84"
["validationRecord",0,"addressesResolved"] ["111.222.333.444","2a01:4f8:141:333::84"]
["validationRecord",0,"addressUsed"] "2a01:4f8:141:333::84"
["validationRecord",0] {"url":"http://www.my-domain.de/.well-known/acme-challenge/_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw","hostname":"www.my-domain.de","port":"80","addressesResolved":["111.222.333.444","2a01:4f8:141:333::84"],"addressUsed":"2a01:4f8:141:333::84"} ["validationRecord",1,"url"] "http://www.my-domain.de/.well-known/acme-challenge/_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw"
["validationRecord",1,"hostname"] "www.my-domain.de"
["validationRecord",1,"port"] "80"
["validationRecord",1,"addressesResolved",0] "111.222.333.444"
["validationRecord",1,"addressesResolved",1] "2a01:4f8:141:333::84"
["validationRecord",1,"addressesResolved"] ["111.222.333.444","2a01:4f8:141:333::84"]
["validationRecord",1,"addressUsed"] "111.222.333.444"
["validationRecord",1] {"url":"http://www.my-domain.de/.well-known/acme-challenge/_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw","hostname":"www.my-domain.de","port":"80","addressesResolved":["111.222.333.444","2a01:4f8:141:333::84"],"addressUsed":"111.222.333.444"}
["validationRecord",2,"url"] "http://my-domain.de/.well-known/acme-challenge/_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw"
["validationRecord",2,"hostname"] "my-domain.de"
["validationRecord",2,"port"] "80"
["validationRecord",2,"addressesResolved",0] "111.222.333.444"
["validationRecord",2,"addressesResolved",1] "2a01:4f8:141:333::84"
["validationRecord",2,"addressesResolved"] ["111.222.333.444","2a01:4f8:141:333::84"]
["validationRecord",2,"addressUsed"] "2a01:4f8:141:333::84"
["validationRecord",2] {"url":"http://my-domain.de/.well-known/acme-challenge/_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw","hostname":"my-domain.de","port":"80","addressesResolved":["111.222.333.444","2a01:4f8:141:333::84"],"addressUsed":"2a01:4f8:141:333::84"} ["validationRecord"] [{"url":"http://www.my-domain.de/.well-known/acme-challenge/_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw","hostname":"www.my-domain.de","port":"80","addressesResolved":["111.222.333.444","2a01:4f8:141:333::84"],"addressUsed":"2a01:4f8:141:333::84"},{"url":"http://www.my-domain.de/.well-known/acme-challenge/_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw","hostname":"www.my-domain.de","port":"80","addressesResolved":["111.222.333.444","2a01:4f8:141:333::84"],"addressUsed":"111.222.333.444"},{"url":"http://my-domain.de/.well-known/acme-challenge/_bL98lTvqMOeJG-NCeLzl2Z3VWUm7EJBa1i6IEBDuLw","hostname":"my-domain.de","port":"80","addressesResolved":["111.222.333.444","2a01:4f8:141:333::84"],"addressUsed":"2a01:4f8:141:333::84"}] ["validated"] "2022-06-13T08:41:47Z")

Answer 1

I've finally found the solution. Laravel Forge does not support IPv6 out of the box. So you either have to configure Forge to use IPv6 as well or remove all AAAA records pointing to the server managed by Laravel Forge.