I have some issue

Same for me. I'm being redirected like this:

https://app.leantesting.com/

-> 302: https://app.leantesting.com/en/sign-in
-> 302: https://auth.crowdtesting.com/evaluate/LT
-> 302: https://auth.crowdtesting.com/authorize/LT

And after a second or two it starts redirecting again all the way to infinity (I killed it after a few hours).