Can't connect to NSA325 via SMB with new laptop

Hi,

I have a new laptop and can no longer connect to my Zyxel NSA 325 v2 via SMB. I have SMB V1 enabled on the new laptop, but any attempt to connect via Windows Explorer fails. I can access the NAS via the browser and its network address, but not via SMB.

I can still access the NAS via SMB using another laptop. I have compared the network settings between the two laptops and also the stored credentials in the key manager (%windir%\System32\rundll32.exe keymgr.dll,KRShowKeyMgr). All settings seem to be the same. Do you have any idea what else could be causing the connection problem via SMB with the new laptop?

Update: In the meanwhile I have deleted all the entries in the credentials manager of the 'existing' laptop and also rebooted it. Curiously I can still logon to the NAS w/o entering the credentials. I've also executed 'net Use * /delete' but it says  that there are no entires in the list. So I ask myself where the credentials are stored/cached and how to reset/delete it.