Connection test to Sybase Adaptive Server failed with "This routine cannot be called since an asynchronous operation is currently pending." error, and "sybase: Message String: Login failed." message was logged in sybase.log.
Sybase Adaptive Server does not provide any detailed information if user failed to login, because of preventing malicious attacks. So, using Auditing function on Sybase Adaptive Server is required for confirming the cause of the login failure.
Adaptive Server Enterprise 15.0 > System Administration Guide: Volume 1 > Auditing > Understanding the audit tables
Auditing login failures
Although client applications may fail to login for many reasons, Adaptive Server does not provide them with any detailed information about the login failure. This is done to avoid giving information to malintentioned users attempting to crack passwords or otherwise breach Adaptive Server?s authentication mechanisms.