@Dizz00 https://mangadex.org/settings
Set "MD
@H Port Limit" to :443, see if that makes a difference.
Try changing your DNS servers, using a VPN or disabling any web filters you have, we've had lots of issues recently with ISPs forcing McAfee's filtering onto home connections and injecting their certificate into blocked sites, which causes browsers to throw an error.
We haven't changed anything that would impact site accessibility in weeks, for the record, so I can't think of anything on our end that would have started this a few days ago.