A worker process failed to respond to a ping.
A process serving application pool %1 terminated unexpectedly. The process id was %2. The process exit code was 0x%3
All worker process threads were busy or blocked.
Consider increasing the application pool’s PingResponseTime property if the application pool is too busy.
Or, use Orphaning to determine what the threads are doing. Orphaning allows you to configure a command-line executable to run when a process fails to respond to a ping. One such example would be to use a debugger to produce a dumpfile for later analysis.