Technical Guide: Managing Split 7-Zip Archives (SS-MaiSS-003_v.7z.002)
Knowing this will help me give you specific troubleshooting steps.
If you are still having trouble opening the file, could you tell me:
This file format suggests it is part of a ( .7z.001 , .7z.002 , etc.), likely containing technical, project, or assessment data (indicated by "SS-MaiSS-003").