I have had issues with the DRM admin password expiring. This is obviously not a situation anyone wants and it seems that DRM ignores the "no password expiry" option as well. The only fix I have found is running the SQL script below:
SET [d_password_expire_date] = '2035-01-01 01:01:01.00'
,[b_exclude_from_timeout] = 1
,[b_no_password_expiration] = 1
,[b_exclude_from_lockout] = 1
WHERE c_user_name = 'ADMIN'
Obviously altering the name of the DRM database for your own.