Clearly the site has issues and they know it as the ADR tool is producing user error message they coded it to respond to a user under specific conditions, "We're sorry, there is a problem searching for Table Service reservations at this time." It appears to work randomly, so there is an issue with the site's performance, but probably not the structures that define it. Tech Support often are not the one's managing a site, but just processing issues to ensure they get to the right people to resolve. I say this is a site performance issue.