Final answer:
The first check performed by an administrator when a user receives an error message when logging into Salesforce is to view the login history. If needed, they can then reset the password or unlock the user. Changing the accepted IP ranges may also be considered.
Step-by-step explanation:
The first check performed by an administrator when a user receives an error message when logging into Salesforce is to view the login history. This allows the administrator to see if there are any specific error messages or unusual activity that may be causing the issue. By reviewing the login history, the administrator can gather important information to help troubleshoot and resolve the problem.
If the login history does not provide any useful insights, the admin may then proceed to reset the password or unlock the user, depending on the specific situation. Resetting the password would be necessary if the user has forgotten or mistyped their password, while unlocking the user would be useful if the user's account has been locked due to multiple failed login attempts.
Changing the accepted IP ranges may only be necessary if the error message suggests that the user's IP address is not within the allowed range. This is less common and usually requires further investigation to determine if it's the root cause of the issue.