Safari can't establish a secure connection to the server "idmsa.apple.com"

Hi,

I am not able to login to this forum, i keep on getting the error

I read another post, which discussed, which sounded similar, but this person had virus software - i do not use any, so that's not it.

I am able to login using FireFox though, and that's how i was able to post this message.

Seems like I should be able to do this with Safari, and very much would prefer this :)

FWIW, I'm using macOS High Sierra, 10.13.6

thanks in advance for any help you can provide