AbleCommerce Shopping Cart Software

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

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

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