Please run
host acme-v01.api.letsencrypt.org
curl -X GET -I --connect-timeout 10 -H "Pragma: akamai-x-cache-on, akamai-x-get-cache-key, akamai-x-get-true-cache-key, akamai-x-get-request-id, akamai-x--meta-trace, akama-xi-get-extracted-values, akamai-x-get-extracted-values, akamai-x-get-nonces, akamai-x-get-ssl-client-session-id, akamai-x-cache-remote-on, akamai-x-get-client-ip" https://acme-v01.api.letsencrypt.org/
traceroute acme-v01.api.letsencrypt.org
It may be the case that the timeout problem only occurs on POST requests, I saw this happening previously, which ultimately resolved itself but we never tracked the cause down.
There is a possible workaround to override the IP address of the API server in /etc/hosts. If you want, you could try point the domain to 23.49.216.139 or another location, and see if Certbot succeeds against that.