Are you clicking the blue update button after you choose your logo?
If you are, are you presented with any error messages?
No message at all
If not, when you edit the entry after attaching a logo to it, do you see the logo?
No it is not saving to the clients profile, everything else in the profile is saved, just the logo doesn’t
If not, are you able to upload images to the WordPress Media Library? The underlying code for the image upload in Connections simply uses the same WP code which handles/processes uploads. So if one works, the other should.
Media library uploads work fine.