Saving email template error

[mbartens]

I duplicated and saved an email template on my Staging Server and everything work fine.
When I try to do this on the production server I get this error:
Client Error

Your browser (or proxy) sent a request that this server could not understand.

If you think this is a server error, please contact the webmaster

I'm thinking it's a setting on the server or maybe IIS somewhere. Does anyone know where? TIA

[mazhar]

Try cleaning your browser cache and cookies and then try again. Also maybe try some different browser, see if it makes any difference.

[mbartens]

Turns out it was the Web Application Firewall on the server causing this.