3470101 - Datasphere connection validation fails with error "ABAP connector(Axino) ABAP connection check FAILED: request failed: rc=1, msg="Message: Logon data incomplete.\nCode: CALL_FUNCTION_SIGNON_INCOMPL""

When validating a connection in Datasphere, the following error is raised alongside the below dump in the backend source system:
Connection "Connection_name" is valid, but not all features are available.
- Data flows can’t be used because of errors in the connection.
- Replication flows can’t be used because of errors in the connection.
- Remote tables are enabled.
- Model Import is disabled.
 
Data Flows: Cause: ABAP connector(Axino) ABAP connection check FAILED: request failed: rc=1, msg="Message: Logon data incomplete.\nCode: CALL_FUNCTION_SIGNON_INCOMPL"
 
Please refer to SAP Note 2849542 for more information.
Replication Flows: Cause: ABAP connector(Axino) ABAP connection check FAILED: request failed: rc=1, msg="Message: Logon data incomplete.\nCode: CALL_FUNCTION_SIGNON_INCOMPL"
 
And the dump:
Category               Installation error
Runtime Errors         CALL_FUNCTION_SIGNON_INCOMPL
Date and Time          
 
|Short Text                                                                                        |
|    Logon data incomplete.                                                                        |
 
|What happened?                                                                                    |
|    Installation error                                                                            |
|                                                                                                  |
|    The current program had to be terminated because of an error when                             |
|    installing the SAP system.                                                                    |
|    ABAP program "SAPMSSY1" had to be terminated because the logon process could                  |
|    not be completed.                                                                             |
|    could not be completed.                                                                       |
 
(...)

|Error analysis                                                                                    |
|    The logon data for user " " is incomplete.                                                    |

SAP Datasphere

When validating the connection in Datasphere, the error mentioned in Symptom is shown.

The dump CALL_FUNCTION_SIGNON_INCOMPL usually will be raised when an application performs a remote function call with incorrect logon information.

Please verify the username and password maintained in the Datasphere connection and repeat the connection validation.

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Datasphere, CALL_FUNCTION_SIGNON_INCOMPL, message: logon data incomplete, logon data incomplete, ABAP, connector, connector(axino), connection failed, request failed: rc=1, msg="message: logon data incomplete.\ncode: CALL_FUNCTION_SIGNON_INCOMPL", connection,  , KBA , DS-DI-CON , Connections , Problem