Issue Unable to issue SSL Cert: acme-challenge token is not available

[laurenzmader]

I am aware that this question has been asked a few times already, but sadly the answers didn't provide a solution for me.

The following error is being repsonded when trying to issue a Let's Encrypt SSL Cert via the Plesk interface:

The authorization token is not available at http://api.main-domain.eu/.well-known/acme-challenge/SPp6mdPeD9gQKo5DIRLpUaYmCc1mYHybCBW.

The subdomain is reachable via the browser. So I assume that the DNS at the registrar is configured properly.

I think that the problem might stem from the automatic HTTPS redirection, since all requests on http://api.main-domain.eu are redirect to HTTPS... and Let's Encrpyt is requesting acme-challenge via the http version.

How do I completely deactivate the https redirection for the subdomain — disabling the "Permanent SEO-safe 301 redirect from HTTP to HTTPS " option unfortunately didn't do the job.

.. but also the problem could be something completely different. I am happy about any leads and suggestions.

Thank you very much,
Laurenz