There are a couple of places to check:
1. On the CABI server, open the ODBC control panel and test the CABI-SDM ODBC connection (starts with casdm_<SDM hostname>) with the 'ServiceDesk' user credentials. If it fails, you need to update the user credentials
2. Open the Universe Designer and open the CA ServiceDesk OOTB Universe. Open TOOLS-CONNECTIONS and ensure that the CASD ODBC connection tested in step #1 is being used. Test the connection. If it fails, you need to update the user credentials