Event ID 2002 warning - Front End HTTP Proxy

Hi

We are receiving the below warnings on CAS which are causing client connectivity problems. I have searched internet for solutions but as yet cannot find any. I also cannot seem to find a way to increase this 5000 limit. Setup is multiple CAS / mailbox servers. Is anyone able to provide any advice?

MS Exchange Front End HTTP Proxy

Event ID 2002 Warning

[Eas] The number of outstanding proxy requests for mailbox server xxxxxxxx has exceeded the max limit 5000. Current request will be rejected.

[Ews] The number of outstanding proxy requests for mailbox server xxxxxxxx has exceeded the max limit 5000. Current request will be rejected.

Cheers

Russell