MySQL 1045 "Access Denied for User": Three Real Causes

Symptom

Cannot connect; ERROR 1045 (28000).

Wrong password, wrong host pattern, or auth plugin mismatch.

1. The host part of the grant mattersSELECT user, host FROM mysql.user WHERE user='app'; # app@localhost vs app@%

2. Old client vs caching_sha2_passwordALTER USER 'app'@'%' IDENTIFIED WITH mysql_native_password BY '...';

3. Apply the grant you think you appliedGRANT ALL ON appdb.* TO 'app'@'%'; FLUSH PRIVILEGES;

One user per app; grants in migrations, not muscle memory.

Spinning up a fresh box to reproduce or escape this error?

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Last reviewed 2026-10-02 · NinjaOps SEO grid · DevOps blog