Certificate problem

I want to give traefik my lets encrypt certificate. My url is registered (I use a subdomain test.domain from united domains) and the certificate is valid. Port 80 on my server is open. But ACME response:

time="2021-12-02T23:49:59Z" level=error msg="Unable to obtain ACME certificate for domains "test.url.com":
unable to generate a certificate for the domains [test.url.com]: error: one or more domains had a problem:
\n[test.url.com] acme: error: 400 :: urn:ietf:params:acme:error:connection ::
Timeout during connect (likely firewall problem)\n" rule="Host(test.url.com)
&& (PathPrefix(/api) || PathPrefix(/dashboard))" providerName=letsencrypt.acme