mapped drive connectivity breaks on crash unable to connect to peer

network drive mapping from peer to peer breaks on crash. 

the access to the main pc over the network using correct credentials for a user on that pc seems to be denied claiming

\\ [peer server] is not accessible you might not have permission to use this network resource..........

The pcs are on the same subnet, wired to the same router and both are in the workgroup "workgroup".

PCs were originally set to use password protected access as using the other radio button 'turn off' did not work.

I tried resetting it both ways.

file and printer sharing are on.

Network is set to private.

Permissions were set to everyone, full control when i originally set it up.

I still had to map the drive originally using credentials from an admin user on the peer server.

By peer server I mean a pc with a directory shared out of the drive to allow a small accounting program to access the main file from both pcs.

This has happened before i would like to stop it permanently