Small letters only for registration

I am not entirely sure, but I have this theory, that if a user tries to register using capital letters in his nickname/Email, Synapse gets messed up a bit. It sends the email, but when a user clicks the link to confirm the email - the new user does not get created.
I looked into logs of Synapse and I found these lines:
```
2020-05-28 23:24:29,676 - synapse.handlers.ui_auth.checkers - 150 - INFO - - Getting validated threepid. threepidcreds: ({'client_secret': 'c680f116-68c9-4c5b-8276-6cd82ffc490f', 'sid': 'MeXzueddUPUhgiMK'},)
2020-05-28 23:24:29,678 - synapse.storage.database - 517 - WARNING - - Starting db txn 'get_threepid_validation_session' from sentinel context
2020-05-28 23:24:29,679 - synapse.storage.database - 556 - WARNING - - Starting db connection from sentinel context: metrics will be lost
2020-05-28 23:24:29,684 - synapse.http.server - 81 - INFO - - SynapseError: 401 -
```
And then since that doesnt work, the timer for email confirmation for that particular user is on, so other attempts to register via RiotX also don't work.

Riot Web does not allow capital letters upon registration, Maybe RiotX shouldn't either?

(Although as I said, Im not exactly sure why all this happen, so please test it on your side. Maybe its a Synapse bug?)

Thanks

UPDATE:
I have tested again, using capital letter and it seems to have worked now. No idea...
MAYBE that was because a user left the RiotX client or pressed BACK while waiting for email confirmation? Maybe thats why user was not created when he pressed the link received (which said that email is confirmed...)?

What does that error mean anyway (SynapseError: 401 - )?

Thanks