Automatic certificate management with letsencrypt for custom domain not working

On my self hosted gitlab-ce I set up a webpage with a custom domain www.example.com pointing (CNAME) to my namespace.mygitlab.com webpage. After selecting the automatic certificate management a message gets displayed

GitLab is obtaining a Let’s Encrypt SSL certificate for this domain. This process can take some time. Please try again later.

but even after waiting a few days, nothing happens and no certificate gets issued.

What is the problem and where do I start to debug this issue?

The log with gitlab-ctl tail gitlab-pages says

{“correlation_id”:"",“duration_ms”:0,“host”:“www.example.com”,“level”:“info”,“method”:“GE
T”,“msg”:“access”,“pages_host”:“www.example.com”,“pages_https”:false,“pages_project_id”:4
,“proto”:“HTTP/1.1”,“referrer”:"",“remote_addr”:“3.14.255.131:58706”,“remote_ip”:“3.14.255
.131”,“status”:307,“system”:“http”,“time”:“2019-11-24T22:30:33Z”,“uri”:"/.well-known/acme-
challenge/<super-secret-token>",“user_agent”:“Mozilla/5.0 (compatib
le; Let’s Encrypt validation server; +https://www.letsencrypt.org)”,“written_bytes”:154}
105 {“correlation_id”:"",“duration_ms”:0,“host”:“www.example.com”,“level”:“info”,“method”:“GE
T”,“msg”:“access”,“pages_host”:“www.example.com”,“pages_https”:false,“pages_project_id”:4
,“proto”:“HTTP/1.1”,“referrer”:"",“remote_addr”:“34.222.229.130:36558”,“remote_ip”:“34.222
.229.130”,“status”:307,“system”:“http”,“time”:“2019-11-24T22:30:33Z”,“uri”:"/.well-known/a
cme-challenge/<super-secret-token>",“user_agent”:“Mozilla/5.0 (comp
atible; Let’s Encrypt validation server; +https://www.letsencrypt.org)”,“written_bytes”:15
4}
106 {“correlation_id”:"",“duration_ms”:0,“host”:“www.example.com”,“level”:“info”,“method”:“GE
T”,“msg”:“access”,“pages_host”:“www.example.com”,“pages_https”:false,“pages_project_id”:4
,“proto”:“HTTP/1.1”,“referrer”:"",“remote_addr”:“66.133.109.36:54204”,“remote_ip”:“66.133.
109.36”,“status”:307,“system”:“http”,“time”:“2019-11-24T22:30:33Z”,“uri”:"/.well-known/acm
e-challenge/<super-secret-token>",“user_agent”:“Mozilla/5.0 (compat
ible; Let’s Encrypt validation server; +https://www.letsencrypt.org)”,“written_bytes”:154}

what does this mean and what could possibly go wrong?

Thanks for any directions

I have the same situation… any ideas?

Any solutions for this? I have the same situation too… Any help would be appreciated.

Same here (for Gitlab-Service at gitlab.com : Pages HTTPS not working