How to Fix MSSQL "Login failed for user"

April 2026

MSSQL login failures are usually credential or connection-string mismatches. Here is the clean Skippr repair path.

Short Answer

SQL Server Login failed for user means the credentials in the MSSQL connection string do not match what the server accepts. In Skippr, this usually means the username, password, or auth mode is wrong.

Once the login works, the rest of the pipeline can continue unchanged.

Why This Error Happens

MSSQL auth can fail even when the database is reachable. The problem is usually the login itself or the way the connection string is built.

• Wrong SQL Server username or password.
• Using SQL auth credentials against a server configured for another auth path.
• Connection string points at the wrong database or instance.
• The login exists but lacks the expected permissions for the target tables.

How to Fix It with Skippr

Validate the MSSQL connection string separately, then rerun skippr connect source mssql with the corrected credentials.

• Verify the SQL Server username and password.
• Confirm the target host, port, instance, and database name.
• Check whether the server expects SQL authentication or another auth mode.
• Reconnect the MSSQL source in Skippr.
• Run skippr doctor or retry skippr run.

When Skippr Is the Better Path

For teams moving MSSQL into Snowflake or BigQuery, this is a good low-friction Skippr use case. Once the source login is fixed, the same workflow can handle extraction, bronze landing, and dbt generation.

That is cleaner than fixing the login in one product and rebuilding the warehouse path somewhere else.