Hello John McCue,
Thank you for posting in Microsoft Community forum.
1.Did you map the network drive manually on your machine? Or did you map the drive via domain GPO? If you map the drive via domain GPO, you should change it via Domain GPO setting.
2.You can try to check the actual IP address of the map drive on your machine by running command: ping ServerName -4
For example:
https://www.winhelponline.com/blog/find-the-ip-address-of-a-mapped-network-drive-in-windows/
3.Please uncheck the option "Reconnect at sign-in" when you delete the mapping and create a new one.
4.Please check if you can map a new drive successfully based on newly created shared folder after the host is re-IPed.
I hope the information above is helpful.
If you have any questions or concerns, please feel free to let us know.
Best Regards,
Daisy Zhou
============================================
If the Answer is helpful, please click "Accept Answer" and upvote it.