I try to enable WLAN (wireless), it finds my router network, but the password that works for all my other devices doesn't work for the printer. I tried several times, and I know the password is correct.
I restarted the printer, and it accepted the password. I don't know why.
Before, the printer restarted after switching to wireless, but apparently that was not enough of a restart. xp
tip: afterwards, I ran into an issue of the print job not being sent to the printer. For this, i just downloaded and reinstalled the full software from the website, restarted my computer, and it worked.