UPS replied with the following:
API URLs starting with www.ups.com/ups.app/xml/ or https://www.ups.com/webservices/ are not currently supported. We are unable to guarantee how long these legacy URLs will remain valid and active.
Please update your URLs as shown in the Developer Guides posted on ups.com. The new URLs begin with https://onlinetools.ups.com.
I downloaded the developer guide and tried two different addresses. Got a different error than before (but the same error for both new addresses). Screen shot attached.