An error occurred during matching - Cant join Lighthouse as the only map

Hello, every time I try to load a into Lighthouse i get this error. I tried looking at this myself with old threads, but none worked.

will I loose all the progress?

Quote from chomp

It looks like some of your files are corrupt, you could try deleting your SPT AND live EFT folders. Install EFT via the BSG launcher again, then install SPT afterwards.