Our Website running with Cloudflare Proxy is slow

We have hosted our Service desk application (JIRA on premise) in an Azure VM.
Between the Azure VM and the end user, we have a cloudflare proxy associated.
in the past few weeks, we have noticed substantial performance degradation of our service desk application when accessed through internet with cloudflare proxy.
Once we disable the proxy, our service desk application works fine with very good performance.
Kindly let me know what could the root cause of this issue.