[HiassofT]

I looked the error deeper and he said something with "certificate". 

The certificate error is caused by a wrong system date - the logs showed your system is still back in june (which is before the begin of the certificate validity date).

The cause of the wrong system date is NTP failing - it's trying to get the current date from a bunch of NTP servers with IPv6 IPs which all fail.

Also check the NTP server section in LE settings - if all NTP server entries are blank the default servers are used which should work.

so long,

Hias