SSO-Ticket in Portal to ECC sporadically not accepted

Hello,

in our SAP Portal I have a strange behaviour with a connector to our ECC system.

When I test the connector it works for the moment (ITS,WAS and connector is OK).

If I try the test the next day it fails (ITS and WAS OK, but SSO-Ticket for connector not accepted).

The connector has the code link:com.sap.portal.systems.sap.SAP_R3_Dedicated

Both system are in the same domain.

Does anyone have an idea?

Thanks & best regards, Bernd Hülsebusch