Hotmail Problems With Squid

Dear All

I am running Squid on RHEL-4 in my office. I have two Linux Proxy servers e.g Proxy-1 and Proxy-2. The users on LAN access internet via these proxy machines but some users whom use Proxy-1 are unable to delete hotmail emails, whereas they can delete hotmail emails on Proxy-2. When deleting hotmail email this message occurs in hotmail

"We can't connect to Windows Live Hotmail right now. Please try again later."

When i check the squid access.log it shows the uder mentioned logs

"TCP_DENIED/403 1249 POST http://co101w.col101.mail.live.com/mail/mail.fpp? - NONE/- text/html"

I have checked ports 403 1249 and allowed them through iptables. I have also put some acls in squid for resolving this hotmail issue.The ports mentioned above listens on proxy server but I dont know why emails are not deleted in hotmail even though users can open, read and write emails in hotmail. Configurations are almost same in my both proxy servers. I need ur precious help and i will appreciate it very much. I will wait for ur valuable replies on this thread.

Thanks for ur time in advance
IFTI