Performance Manager Not gathering data

Hi,

The Flare code on the old CX4 is upgraded on July 12th  on Prod and Dr CX. After the upgrade CX is working fine, gathering data and reports. But the DR CX is not gathering data what could be possible issues??

1. Stats logging is enabled in CX

2.Agents are working fine( what else should I check in agents??)

How to trouble shoot this issue??