With the Windows 11 24H2 update, Microsoft introduced changes to network authentication with SMB: by default, it is not possible anymore to connect anonymously with guest/guest, which is why it now pops up a password dialog. (Home edition got this with 24H2, some other editions had it even before).
However, at this time, ROCK continues to use guest/guest, so you need to reenable this in your Windows client. Microsoft explains this here:
Note: The steps 1-5 of this solution are for NAS where you can create a log-in account with authentication by username and password. You can’t do that on ROCK, and therefore the solution for this starts at step 6 (re-allow guest/guest log-in on the Windows client)