Contribute and Edit feature no longer working

I'm a longtime user of Lightroom CC and have been using the Collaborate feature since it was added. A team member who previously was able to edit and contribute has lost those abilities and can only download .jpg files. I've verified that the invite is correct. I've also created a new album for the images and resent the invite. No luck. I even added the images to an older album that he previously had editing abilities to, yet we are still experiencing the same issue.  We are both using the latest version of Lightroom CC (currently 7.5). Any suggestions would be much appreciated.