Mouthly Job Fails


on every 1st in Mouth cron.php throws errors:
PHP Fatal error: Uncaught Error: Cannot call abstract method DBManager::convert() in /var/www/html/SuiteCRM/modules/Schedulers/ _AddJobsHere.php:390 Stack trace: #0 /var/www/html/SuiteCRM/modules/SchedulersJobs/SchedulersJob.php(539): trimTracker(Object(SchedulersJob)) #1 /var/www/html/SuiteCRM/include/SugarQueue/SugarCronJobs.php(191): SchedulersJob->runJob() #2 /var/www/html/SuiteCRM/include/SugarQueue/SugarCronJobs.php(231): SugarCronJobs->executeJob(Object(SchedulersJob)) #3 /var/www/html/SuiteCRM/cron.php(100): SugarCronJobs->runCycle() #4 {main} thrown in /var/www/html/SuiteCRM/modules/Schedulers/ _AddJobsHere.php on line 390

Jobs running on 1st:
**[Prune Tracker Tables] I think this is the problem
**[ Removal of documents from filesystem]
**[ Prune SuiteCRM Feed Tables]

can someone Help?
Version 7.10.24
PHP 7.0.33-0+deb9u10 (cli) (built: Oct 6 2020 17:08:28) ( NTS )