Error code S0A00 generally means a cable is not connected well. Check all connections from the wall outlet all the way through to your TV. That always works for me when I get S0a00 (seriously!).
After checking for looseness, run the cable directly from the wall into the back of the TV (bypassing all the devices), if that works then one-by-one re-connect the devices to see where the problem lies.
If that doesn't work, this from Xfinity's support site:
Error code S0A00
If you have been receiving the S0A00 error message for more than one hour, a live technician will need to troubleshoot the issue with you. Please determine if the error message is appearing on all TVs in your home, or just one before you contact us. 1-800-COMCAST (1-800-266-2278).
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