PTR M+ Disconnects!

Hi, I want some help understanding why everytime I enter a PTR M+ I disconnect. I can hit the dummies in Dorn for 3 straight hours with no disconnects and then the moment I load into a M+ I disconnect. I log back in and immediately met with another disconnect. My battle net client says it’s updated for 11.1, and this is not an issue on retail. What’s the deal???