I also had the same issue on my first login (the email was verified, btw). The login button just went spinning and nothing happens. Trying the login on Jerboa gave me invalid credentials (it wasn't a mistype, because I used a password manager).
The workaround I did was to do a password reset and use a simpler one (was 50+ chars with special chars on, then changed to 32 chars and no special chars).
Not sure if what fixed was the reset itself, or the new password.
After this, the login went smooth on both the website and the app.
EDIT: And when posting this, the post submit button also kept spinning (the more than 200+ chars issue). But trying in a new tab, the message was actually sent.
And some minute later, on the old tab the message was sent, but the OP post changed from the "improvements and issues" to "The inability to post multiple pictures is holding Lemmy back.", but the comments below mine where for the "improvements and issues", while the comment above where to the other thread.
Actually, hello.1@gmail will go to hello1@gmail.
The one you are thinking I believe is hello+1@gmail will go to hello@gmail