If you get a certification error on repository.solydxk.nl you can edit your sources.list file with these steps:
- In a terminal, type: apt sources
- Change "repository.solydxk.nl" to "repository.solydxk.com" and make sure it begins with "https":
deb https://repository.solydxk.com solydxk-9 main upstream import
- Save and quit: Ctrl-O, Ctrl-X.
- Still in the terminal:
The subdomain forums.solydxk.nl will forward you to forums.solydxk.com. However, if you have visited forums.solydxk.nl before, your browser will have cached the now revoked certificate and tell you that it is unsafe to proceed. Just visit the forum on the community domain: https://forums.solydxk.com
I apologize for the inconvenience.
Source: https://solydxk.com/news/certificate-er ... subdomains