Letsencrypt not working since updated to 1.791

Hello, My SO is Debian 8. I already setup letsencrypt certificates for 3 virtual domains without problems with older versions of virtualmin. Yesterday, i updated to 1.791 and created a new virtual domain. Now, when try to install the letsecrypt certificate from "manage ssl certificate" section the i get an error:

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pre>Updating letsencrypt and virtual environment dependencies...Retrying (Retry(total=4, connect=None, read=None, redirect=None)) after connection broken by 'NewConnectionError('<pip._vendor.requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0xb695cf2c>: Failed to establish a new connection: [Errno -2] Name or service not known',)': /simple/setuptools/

After a lot retrials the process stops and get this error:

ConnectionError: HTTPSConnectionPool(host='acme-v01.api.letsencrypt.org', port=443): Max retries exceeded with url: /directory (Caused by NewConnectionError('<requests.packages.urllib3.connection.VerifiedHTTPSConnection object at 0xb65bd04c>: Failed to establish a new connection: [Errno -2] Name or service not known',))

i can't find any info about this error and im really lost.

Port 443 is open and can establish https connection with the website domain using self-signed certificate. The folder .well-known is created and has domain user and group owner which i think is right.

Any help i really appreciate.

Thanks.