SnapShot issues with re-installation

Snapshot's been deactivated for some reason on this website and fails to instal again. I've deleted the plugin files from my server, which seems to work in most cases (10 websites afflicted, see: https://premium.wpmudev.org/forums/topic/snapshot-pro-snapshot-stopped-working#post-1380707); however, in this case, even after the plugin files have been deleted, the installation still fails.

This is the message I get:
Server error status: Internal Server Error [500]

I've enabled support access in wordpress.

Hope to hear from you soon.

Kind Regards,
Dubie Bacino