Octoprint can't log in on my phone

What is the problem?
I use firefox on both my android phone and my laptop. My passwords sync between the two. Since I set up octoprint on the laptop, I have been able to log in with my phone to monitor printing etc. Now I can't; it says that the password or username is wrong. The synchronised details on my laptop work fine, but on the phone they are wrong.

What did you already try to solve it?
I have cleared the cache, and also gone into private mode. Neither will work. I typed into the field on the phone the password displayed on the laptop screen and it was also apparently wrong.
I checked the IP address and it was the same on both machines.

Logs (syslog, dmesg, ... no logs, no support)
It is working fine when my laptop contacts it, so I suspect that the computer logs will show nothing of note - is that right?I'm running Win 10 on my dell laptop, and Android 11 on my Samsung a20e

I have no idea why this has started, or how to approach it, really, as the same password and username work on the laptop