@Alex_Nick - I have checked the logs which you have shared with us and here is the analyzes for it.
2C8C 1198 11/20 22:31:38.527 23 EmIntegration.cs(1800000) NORMAL DpmTimer: Setting Interval to {0}
2C8C 2BC8 11/20 22:31:38.590 07 NotificationManager.cs(47) NORMAL Sending Mail using AuthType = WindowsAuthType
2C8C 2BC8 11/20 22:31:40.722 07 Mailer.cs(134) NORMAL About to send mail 2
2C8C 2BC8 11/20 22:31:40.738 07 NotificationManager.cs(87) WARNING Exception : System.Security.SecurityException: Requested registry access is not allowed.
2C8C 2BC8 11/20 22:31:40.738 07 NotificationManager.cs(87) WARNING at System.ThrowHelper.ThrowSecurityException(ExceptionResource resource)
2C8C 2BC8 11/20 22:31:40.738 07 NotificationManager.cs(87) WARNING at Microsoft.Win32.RegistryKey.OpenSubKey(String name, Boolean writable)
2C8C 2BC8 11/20 22:31:40.738 07 NotificationManager.cs(87) WARNING at Microsoft.Internal.EnterpriseStorage.Dls.NotificationManager.NotificationManager.GetSmtpAuthType()
2C8C 2BC8 11/20 22:31:40.738 07 NotificationManager.cs(87) WARNING The Zone of the assembly that failed was:
2C8C 2BC8 11/20 22:31:40.738 07 NotificationManager.cs(87) WARNING MyComputer
2C8C 2BC8 11/20 22:31:40.753 68 DpmThreadPool.cs(122) WARNING Caught unhandled exception : System.Security.SecurityException: Requested registry access is not allowed.
2C8C 2BC8 11/20 22:31:40.753 68 DpmThreadPool.cs(122) WARNING at Microsoft.Internal.EnterpriseStorage.Dls.NotificationManager.NotificationManager.GetSmtpAuthType()
2C8C 2BC8 11/20 22:31:40.753 68 DpmThreadPool.cs(122) WARNING at Microsoft.Internal.EnterpriseStorage.Dls.NotificationManager.Mailer.Send(String to, String from, String subject, String body, String mailServerName, UInt16 port, String username, String password)
2C8C 2BC8 11/20 22:31:40.753 68 DpmThreadPool.cs(122) WARNING at Microsoft.Internal.EnterpriseStorage.Dls.NotificationManager.Mailer.Send(String to, String subject, String body)
2C8C 2BC8 11/20 22:31:40.753 68 DpmThreadPool.cs(122) WARNING at Microsoft.Internal.EnterpriseStorage.Dls.NotificationManager.NotificationSubscription.SendNotificationWorker(Object param)
2C8C 2BC8 11/20 22:31:40.753 68 DpmThreadPool.cs(122) WARNING at Microsoft.Internal.EnterpriseStorage.Dls.EngineUICommon.DpmThreadPool.Function(Object state)
2C8C 2BC8 11/20 22:31:40.753 68 DpmThreadPool.cs(122) WARNING at System.Threading.ExecutionContext.RunInternal(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
2C8C 2BC8 11/20 22:31:40.753 68 DpmThreadPool.cs(122) WARNING at System.Threading.ExecutionContext.Run(ExecutionContext executionContext, ContextCallback callback, Object state, Boolean preserveSyncCtx)
2C8C 2BC8 11/20 22:31:40.753 68 DpmThreadPool.cs(122) WARNING at System.Threading.QueueUserWorkItemCallback.System.Threading.IThreadPoolWorkItem.ExecuteWorkItem()
2C8C 2BC8 11/20 22:31:40.753 68 DpmThreadPool.cs(122) WARNING at System.Threading.ThreadPoolWorkQueue.Dispatch()
2C8C 2BC8 11/20 22:31:40.753 68 DpmThreadPool.cs(122) WARNING The Zone of the assembly that failed was:
So, seems it is the permission issue with the registry on DPM server. I would request you to please go to below mentioned registry path and check if you have the required permission on it or not.
This should resolve the issue for you. If the suggestions were helpful, click “Accept Answer” and Up-Vote. Feel free to reach out to us if you've additional questions in this regard.