Did some of the configuration variables change ? 
NumberOfStatusPollers    If you plan to monitor large number of hosts, increase this parameter from the default value to approximately 1/10 of host count.
NumberOfConfigurationPollers    If you plan to monitor large number of hosts, increase this parameter from the default value to approximately 1/20 of host count. 
I no longer see these in the configuration and if things did change could you make a list of what changed or whats new ?
			
			
			
				New poller configuration parameters can be found there: https://www.netxms.org/documentation/adminguide/quickstart.html?highlight=pool#basic-server-tuning or there: https://www.netxms.org/documentation/adminguide/appendix.html?highlight=pollerthreadpoolmaxsize#server-configuration-parameters (PollerThreadPoolMaxSize, PollerThreadPoolBaseSize)
All other poller configuration parameters were removed. 
			
			
			
				Cool... Thank you for the info