New users unable to register themselves

My version of HedgeDoc is: 1.10.3

What I expected to happen:

New user can register with their email and chosen password, because environment variable CMD_ALLOW_EMAIL_REGISTER is set to true (also tried 1)

What actually happened:

Mousing over the “Register” button shows a no entry sign and cannot be clicked.

I already tried:

Have also raised with Pikapods who are hosting my HedgeDoc.

I didn’t understand that you have to enter email and password BEFORE clicking on Register. Many systems work the other way round.