You the password will be auto expire in 90 days. It is something that is set by your organization admin for the developer login but it will also affect application user.
To my knowledge you can ask the admin to remove the constrain or In mendix you can use a scheduler to check if the active attribute of user is false and if yes you can change it to true.
You can also achieve this by creating custom login behavior using java.
Hope my answer helps. Reach me out for any queries.