Accessing a NAS from my Mac - annoying popup!

I have a Synology DS220j set up as a storage device and connected to my wired network at home.

In 'managing' the Synology accounts on the NAS, I changed the password for the main account which, understandably, led to connection issues between the Mac and the NAS, so I changed the credentials on my

Mac and I can now access the NAS without issue, except...

When I start my Mac, I get the following notification:

...but it keeps popping up, yet I can still access the Libraries folder and sub folders on the NAS in Finder:

My guess is there's a routine somewhere looking for and not finding the NAS, which I need to amend or stop.

When I first setup the NAS, I enabled it as an "Open at Login" option, but removing that has no effect.  I still get the popup.

I'll reset the NAS account password to the original one to see if that works (the NAS login and password used to be the same as my account login on the Mac), but was wondering if anyone might know how to stop this irritation.

Thank you :-)