SL3 course not registering completion on LMS using Edge (legacy)

Hi, I hope someone can help me. A course I built in SL3 was loaded onto our company LMS (Success Factors). It plays on Edge, Edge Chromium and Internet Explorer but when Edge (legacy) is used it doesn't mark course completion.

I uploaded the course to SCORM Cloud and Completion registered as 'complete' and Success as 'passed'.

I can send through the source Storyline file and/or SCORM files as long as there is non-disclosure of any information shared.

Thanks, Brian