Nas DNS-343 = Failed to map drive

Hello, I have a problem with my old D-Link DNS-343 NAS.

My power supply had an issue that I had to replace (nothing serious so far), but while I was changing it I left the NAS turned off. Now that I’m rebooting it, my disks are inaccessible in "This PC" when I launch the "easy search 4901" application with which I had configured it; I can see it with my 4 drives, but when I select the drives to connect it returns the error = Failed to map drive.

I don’t know if it’s the password I can’t remember, it goes back a long time since I last used that password, and while searching the net I found 2-3 pieces of info about resetting the NAS with the button on the back to connect as admin by default, but here’s my question: will I lose all my data by resetting? or is there another way to recover my drives?