SentinelOne is an antivirus solution, that uses shadow copy as a protection against virus attacks. Unfortunately, that causes Shadow Copy storage to get filled up and, in turn, causes Rapid Recovery backups to fail because no more shadow copies can be created.
It's possible to 'flush' all shadow copies by changing shadow copy storage limit to 320MB and then back to the original limits (10% of disk size) or to 'No Limit". However this will remove all SentinelOne restore points.
It's recommended to uninistall SentinelOne agent and use a RapidRecovery as a comprehensive backup and restore solution.