Multi User Browser Friends unable to joined/see the joined session

I have a issue when i launched the multi user server based on the settings that i have put on udp message with my ip address and my friend ip address. After that, i received an error message where it says workspace validation failed ue5 with my file storage name such as E:\myProject\xx. … … tgt with contains local changes before joining a multi-user session.Can you recommend me how to solve the issues kindly. We need your help on these issues. It’s urgent… Thank you.