HFSS Convergance problem

Dear All,

Using the HFSS 10, After Running the simulation that calculates the eigenmode resonance frequencies of a magnetron cavity, it stops and gives me the following message:

[error] Recovering adaptive solution, process abc3d: Eigenvalue calculation failed to converge. (12:34 PM Feb 17, 2007)

[error] Simulation completed with execution error on server: Local Machine. (12:34 PM Feb 17, 2007)

Do any one have any clue about why this happens ?!
My Best Regards,
Goher

Solution setup-->Option-->Target must leas (for example:.1) or Uncheked. O r Number of pass is greater (Solution setup-->General-->Number of pass)