Same Rig Manager problems here, can't connect to Rig Exchange, test login credentials fails, name/password verify fails and RM Warning pops up saying "RM performing task, do you want to quit?" Tried downgrading to 3.3, tried reinstalling RM 1.5, tried redoing name/password ... but no luck fixing RM/RE authentication issues.
Interestingly, if I simply ignore all the pop-ups, I can preview and load from the Rig Exchange so it's still functional for me. Trying to be a good KPA citizen, I've opened a ticket and am in conversations with Support.
OSX 10.11.4
KPA Sys 4.0.2
RM 1.5.40