Receive String Error: How do i write a regular expression for the below string

A Monitor Receive String should be a regex.

However, you are trying to match the plain text response, but it contains characters that could be part of a regex. The solution is to escape the offending characters

\{\"Job Server Health Check\":\{\"healthy\":true\},\"Quartz Scheduler Health Check\":\{\"healthy\":true\},\"deadlocks\":\{\"healthy\":true\}\}

However, I'd be tempted to not try to match the entire string, and just look for

\"Healthy\":true