Biztalk SSO Error The ticket does not have the correct

Hi

I USE SSO In Send port for Set WCF Service Credential For call Service Layer .

When I Call Service in loop for example :

for (int i = 0; i < 120; i++)
            {
                 var tt = p.GetTelePhoneByPostcode()
            }

after 40 or 60 Call in loop  I Get Error.

i see this error in event viewer:

The ticket does not have the correct format.
 Application Name: TM.ESB.Services.

How the format is incorrect after some success call !!?