Hi is there any idea when i tries to fetch theme in suite commerce site

Issue is probably in one of your Active Extension's "SC ExtMech Extension" record OR in Extension's manifest.json (Both should be consistent with each other). Try fetching your extensions one by one to your local setup to find which extension is causing issue. We faced similar issue when we manually changed VENDOR on SC ExtMech Extension record. Setting the original vendor solved the issue.

Okay thanks @Sarim Khan