NCP 1.35.0 Letsencrypt suddenly fails with timeout

Hello! I’ve been using NCP for more than a year. Running version v1.35.0 on a raspberry pi.

Now letsencrypt cert update fails (timeout during connect).
I did not change anything in my setup. ports are accessible and the adress is valid and up to date.
Did anyone have the same issue recently and found a solution?

certbot.errors.FailedChallenges: Failed authorization procedure. […] (http-01): urn:ietf:params:acme:error:connection :: The server could not connect to the client to verify the domain :: Fetching […]: Timeout during connect (likely firewall problem)


Could be:
DNS services slow,
Interupted or bad internet connection.

Wait for cpl minutes and try again, or run certbot manually using DNS txt record to verify.

1 Like


DNS server is set to Google (

Internet connection is flawless for everything else.

I tried the letsencrypt web interface a couple of times over the last days.

run certbot manually using DNS txt record to verify.

Can you point me to the correct instructions for this? Thank you!

I found the cause of the problem: nc-httpsonly i.e. “Force HTTPS”

Apparently checking this option makes a regular certificate renewal impossible? It might be a good idea to point that out somewhere either in nc-httpsonly or letsencrypt

Still an existing bug in v1.46.9. Letsencrypt renewal fails multiple times, turning nc-httpsonly off required to make it work.