SCORM courses losing progress after logging out and in

Summary

User inputs data to Scorm course and used to return to same place when logged out and back in but now data has disappeared

Content

We are hosting SCORM 2004 4th Edition courses developed in Articulate Storyline 360 due to the amount of data we collect in our courses. They were working correctly ie. when a user saved the course after the 1st session and logged out and back in a few days later their information was still there and they were able to move to do the next part of the course.

What has started happening now is that when the users log back in their data has gone and they are back at the first part of the course as if they had entered it for the first time. This has started happening in the last week or so. Generally our clients log in about once a week so that they can reflect on their progress that week.