My hummingbird plugin doesn't work properly: " The performance test didn't return any

I'm trying the performance test from Hummingbird, firstly it was giving me a 500 error page, after increasing the PHP memory limit it is stuck on The performance test didn't return any results.
This probably means you're on a local website (which we can't scan) or something went wrong trying to access WPMU DEV. Try again and if this error continues to appear please open a ticket with our support heroes, can you help me?