BALTIMORE — A large number of Marylanders had signed up to get the coronavirus vaccine at a sports stadium only to have the appointments canceled.

The Baltimore Sun reported Sunday that most people had signed up using an invalid link.

The vaccine appointments had been scheduled to occur at M&T Bank Stadium.

The University of Maryland Medical System said the booking link was made “inadvertently” public.

Spokesman Michael Schwartzberg said people who had signed up have since been notified that their vaccines were canceled because eligibility couldn’t be confirmed.

He said that a non-public website had inadvertently made an appointment booking link discoverable.

M&T Bank Stadium is scheduled to open Thursday as the state’s third mass vaccination site.