Can't send password protected zip files 1

[NATCAT]

Hi All,
I'm suddenly getting this error when I try to send or recieve password protected zip files.

550 5.5.0 Mail rejected for container policy reasons

Can someone give me an idea of how to troubleshoot this ?
FYI: I can send and recieve other password protected files, just not zipped ones

 

[xmsre]

Check you antivirus and/or spam control software. Many have recently started treading passworded zip files as an exploit and block them.

http://www.geekzone.co.nz/content.asp?contentid=3050

http://www.policypatrol.com/docs/PP3-FeatureList.pdf

http://www.xwall.us/xwallrelease.htm

 

[NATCAT]

xmsre,

You were on the ball.
After upgrading my firewall software there was an option to block encrypted attachments in the antivirus configuration.

The reason why I could send excel password protected files was that I only needed to use a password to MODIFY them, I can read them without using a password. The zip file on the other hand needed a passward to view the file.