I've further investigated this issue and it seems that all users who are receiving the error message
are using Windows XP SP3 or Windows Vista.
The CDN used by Discogs recently moved to dropping support for TLS 1.0 and TLS 1.1 so that Discogs itself also moved on to the more recent and more secure TLS 1.2 standard for HTTPS connections.
Unfortunately, TLS 1.2 is not supported by Windows XP SP3 and Windows Vista, so that connections to Discogs won't work there.
Kind regards
– Florian