Anyone not able to login into Nexus from MO v1.3.11 can simply fix it by doing these steps here:
I already did it and MO now logs into Nexus again. It's just adding a line to the bottom of the host file and you're done. Will take less than a minute and you don't need to update/switch to MO2.
As for the MO discord, I don't know if this forum is even active anymore but the current link on the official post for it doesn't work because it's expired. If anyone could send me an invite and/or make another link that doesn't expire, that would be great. I would like to let people know in the discord of the easy fix if they wish to continue using MO v1.3.11.