First please try to ping to the server IP to check is connect or not. If the PC is connect to the server. Please following the step below to check and enable the insecure guest logons.
Click the Start Button.
Type in “Edit group policy”
Click on “Edit group policy”
Select “Computer Configuration”
Select “Administrative Templates”
Select “Network”
Select “Lanman Workstation”
Double click on “Enable insecure guest logons”
For Enable insecure guest logons, please select “Enabled”
Click on Apply Button
Click on Ok Button