It's a little misused term error if "server Reached MaxClients setting, consider raising the MaxClients setting". It is more a notification server administrator is warned that limit has been exceeded "MaxClients". It is true that exceeding this limit leads to instability and Apache automatically operating problems Website [...]
The MaxClients directive sets the limit on the number of simultaneous requests That will be served. Any connection Attempts over the MaxClients limit queued Will BE Normally, up to a number based on the ListenBacklog Directive. Once a child process is Freed at the end of a different request, the connection Will THEN BE serviced.