"not Acceptable" 406 Error

Hi,

I'm having a problem when i go to manually add a payment ton an order I get the

following message:

"Not Acceptable

An appropriate representation of the requested resource could not be
found on this server.

Additionally, a 406 Not Acceptable error was encountered while trying
to use an ErrorDocument to handle the request."

Also, when I go to send a client an email letting them know their downloads
are ready for download, it just hangs at "sending" and doesn't really
progress.

Was working fine Thursday evening and it threw up this error on Friday, nothing has been updated or any settings changed on my side.

Any suggestions?

A 406 Not Acceptable error is an HTTP status code that means the server is unable to provide a response that matches the client's request format. 

Something must have changed on your host to cause this. Maybe a firewall added. 

You should contact your host and let them know you are getting a 406 error on something you didn't previously. And nothing in Sytist would have changed to cause this (for when they blame the software)

Thank you Tim