When logging in with a user that was created after updating to FE 7.87 patch 24 through patch 28 the user is unable to login with the error: Invalid Login, You have entered an invalid User ID or Password.
Users may also see error: Unable to establish database connection. Please refer to the Knowledge Base article 48382.
This issue has been resolved in 7.87 patch 29. If a new user was created between on patch 24 - 28 and cannot be used to log in, a new user will need to be created on patch 29 or higher.