Cannot login with student account

I have created a small number of classes under the teacher resources area (UK) and I have allocated Python to my classes. I have tried to test some of the student accounts by logging in with a couple of the auto created usernames but I cannot login with any of the usernames from a particular class. I have changed the password for the class so it is different from that of a class that works, but to no avail.
I have tried using Chrome which works fine with one class, but not with another. I just keep getting ‘invalid login’ errors. There are 26 students in the problem class and 21 in the class that works OK.
Can anyone shed any light on this? The data entered is in the same format, i.e. just student forename and surname.
Best wishes
Ingrid Evans

@kelvin14, could you have a look at this one please?

Same problem here! PLEASE HELP! None of the students can log in

I am having trouble with the same problem as well, has there been any response?

Not heard anything Kalrb. I went to look at the tracker for a class of mine today and it said that they had done 0% which is rubbish! No idea what is happening to my classes and I’m reluctant to add others now. Best wishes