Unable to log into Duolingo App

I just got a new Fairphone 6 with e/os preinstalled. The installation of the duolingo app went fine, but I can’t seem to log into my account. Username and password are definitely right, and on other devices the login works fine. Yet I’m told that the username or password is incorrect.
Can anyone help me?

Regain your privacy! Adopt /e/OS the deGoogled mobile OS and online servicesphone

do you have cloud messaging / device registration in microG settings enabled in Settings → System → microG ?

Yes, that’s enabled…

duolingo has this super lengthy process to create an account, otherwise I’d create one and debug this.

You need logfox or logcat to give you some loglines to understand what’s the underlying failure.

Though I’d expect a microg issue if many users are affected. You also do not have the PWA version installed right?