This error means that the password used (as defined in Credentials) is incorrect. This is almost always due to the account having its password changed in Active Directory but not changed in PDQ Deploy (or PDQ Inventory). When a password is changed in Active Directory (or Windows for local credentials) then it needs to also be changed in PDQ Inventory. To update the password go to the Credentials panel under File / Preferences and choose "Edit Credentials".
It is recommended that the accounts used by PDQ Inventory or PDQ Deploy have their password policy set to Never Expire. This is a common practice for accounts that run Windows Services. If having this password policy is not an option for your environment then it is important to remember to update the passwords in PDQ Deploy and PDQ Inventory after changing them in Windows.
If the above does not apply to your situation, please see the following article on resetting the Background Service on the PDQ console machine: The Service Did Not Start Due To A Logon Failure
Another option is that the password was entered incorrectly in Credentials. Verify that the correct password was entered.
Other possible logon/password issues are covered in the following: