Symptoms
Microsoft Exchange Web Service (EWS) becomes unresponsive on servers that run Microsoft Exchange Server and that have more than 100 GB of RAM. When you check the performance log, you notice an entry that reports, "High %Time in Garbage Collection (GC)."
Causes
The MSExchangeServicesAppPool application pool is not configured to run in Server GC mode on systems that have more than 100 GB of RAM installed.
Resolution
To fix this issue, install the following cumulative update:
Cumulative Update 14 for Exchange Server 2019 or a later cumulative update for Exchange Server 2019
