"Safe handle has been closed" exception on TapiCall.Privelege setter

Oct 23, 2015 at 4:10 PM
Edited Oct 23, 2015 at 4:11 PM
Operators have sometimes a problem with hanging up calls. Before dropping call we get control over it by
tapiCall.Privelege = Privilege.Owner;
and sometimes this code throws exception
System.ObjectDisposedException: Safe handle has been closed
   at System.Runtime.InteropServices.SafeHandle.DangerousAddRef(Boolean& success)
   at System.StubHelpers.StubHelpers.SafeHandleAddRef(SafeHandle pHandle, Boolean& success)
   at JulMar.Atapi.Interop.NativeMethods.lineSetCallPrivilege(HTCALL hCall, Int32 privilege)
   at JulMar.Atapi.TapiCall.set_Privilege(Privilege value)
Is there any way to solve this problem? Thanks in advance.
ATAPI v.1.4.0.