The PDM server has some issues with licensing once its been restored.
Once its been restored from backup the license manager is broken. to fix it do the following:
Open the Solidworks 2018 licensing manger:
1: Select Move to a new or upgraded computer
2: Confirm license server information, though it should be right.
2.5: if it failes, answer "yes" to the activation wizard. then go through all that again. it should work
3: If you did everything right, select finish.
Reboot the server and it should be fixed.