bug sending calendar from different version of outlook

[farzadha2]

Hi
Currently were getting an issue when a user sends from outlook 2021 to 2019 were getting this issue

Thank you

CalDavSynchronizer.DataAccess.WebDavClientException: Response status code does not indicate success: '412' ('Precondition Failed'). Message:
<?xml version="1.0" encoding="utf-8"?>
<D:error xmlns:D="DAV">Precondition Failed</D:error>
at CalDavSynchronizer.DataAccess.HttpClientBasedClient.WebDavClient.<EnsureSuccessStatusCode>d__10.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at CalDavSynchronizer.DataAccess.HttpClientBasedClient.WebDavClient.<ExecuteWebDavRequest>d__9.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at CalDavSynchronizer.DataAccess.HttpClientBasedClient.WebDavClient.<ExecuteWebDavRequestAndReturnResponseHeaders>d__8.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at CalDavSynchronizer.DataAccess.CalDavDataAccess.<CreateNewEntity>d__27.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
at CalDavSynchronizer.Implementation.CalDavRepository1.<Create>d__17.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.ExceptionServices.ExceptionDispatchInfo.Throw()
   at GenSync.EntityRepositories.BatchEntityRepositoryAdapter4.<PerformOperations>d__3.MoveNext()