Slow performance with On-Prem Exchange Server 2019 and Outlook (Migrated from 2013 in 2021)

Question

exchange2019newb

Every 20 to 30 days users across the organization both internal and external notice their Outlook 2019 being to slow and receive "Not responding" errors when opening emails, as well as slow to "Send" emails (15 to 20 secs).

We explored the issue being isolated to Outlook 2019 performance but nothing was found. We turned to the searching Exchange log files and possible network issues within Exchange itself but found no issues with either. In troubleshooting we looked at Exchange services we assumed would resolve the issue but nothing was obvious or stood out.

The only way we found to resolve the slow response issue was to restart the Exchange server. The pattern seems that after 20 to 30 days of uptime the Exchange server and Outlook being to show signs of slow performance and we are unsure as to why.

Any assistance will be greatly appreciated!!