Hi,
Looks like a very old version, so some manual maintenance is due.
First take a backup and then delete the plugin.
Second delete any direct child fvm
directories inside wp-content/cache
or wp-content/uploads
and for each uploads subsite directory.
Third, use a database tool like phpmyadmin to look for on the wp_options
table for each site, for any option_name
that start with fastvelocity_
or fvm_
then delete those rows.
Fourth, install the wp cron control plugin, and look for any cronjobs with fastvelocity in the name, and delete them. After that you can delete the wp cron control plugin.
All references have mostly fastvelocity_
or in a couple of cases fvm_
as a prefix, on version 2.x.x