Can't log in to Runkeeper on Galaxy S4 Active

[qualikjell]

I have made a factory reset on a Galaxy S4 Active running Android 5.0.1. After reinstalling Runkeeper, I can't log in. The e-mail and password works with my desktop and with a newer phone (Galaxy A71). Any suggestions to what can be the problem?

[Mitzzz999]

It's only a suggestion but I would expect some of the older smart phones won't run certain apps properly due to outdated firmware or functions.

[qualikjell]

Runkeeper support had similar ideas. I tried older versions including the one that worked before the factory reset. I also cleared the cache and all data and reinstalled the app. I tried resetting the password. Nothing helped.