I'm getting "13 The data is invalid" for HTTP requests from a device our school has been given by our electricity company to monitor electricity use. I was told it only needed port 80 out to the Internet, so set it up as a firewall client (gateway as TMG server).
Here is what appears in TMG log:
Failed Connection Attempt SRV-FW 26/09/2013 13:20:16
Log type: Web Proxy (Forward)
Status: 13 The data is invalid.
Source: Internal (172.16.4.40:1144)
Destination: ec2-54-246-108-230.eu-west-1.compute.amazonaws.com 126.96.36.199:80
Filter information: Req ID: 09ec2e5a
Object source: (No source information is available.)
Cache info: 0x0
Processing time: 0 MIME type:
Thanks in advance!