It said the server couldn't prove its security certificate but I found the option to proceed anyhow and when I did that it sent me to plesk obsidian and wanted me to sign into that???

Help me out I love moparts but I'm barely hanging on by a thread been trying for months to figure out how to get on it on my phone finally got on here but between this tiny screen and keyboard and it has so many ads it's about useless.

Reads like malware, but malware I am not knowledgeable about clearing.

Plesk was a valid linux website,
but a search indicates it may have been attacked and hacked in December 2023.

On the small screen of an Android cell phone
I have found that
“Samsung Internet Browser” with the Adblock plug in
works better than Chrome Browser with Adblock plug in
for Moparts.

On iOS the Brave Browser with its built-in ad blocking seems to work best on Moparts, and seems way better than Safari.

I get the same thing when I am on my work computer for Moparts and a couple others. I was told it had to do with the security settings on my companies network.
Strangely, if I search Google for "moparts forums" it lets me in and everything works normally. I'm not sure if has to do with the homepage address or what. I just reset my shortcut and moved on.

Check the address..it is now Moparts.org. Might or might not be your issue