To clear this error, try the following tips.
STEP 1: Many issues, such as missing channels, can be fixed by “refreshing” your receiver. Go to your My Equipment page and select the Refresh Receiver link next to the receiver having trouble.
Still seeing Error Code 721? Try Solution 2.
Solution 2: Check your channel lineup
STEP 1: Sign in to directv.com
STEP 2: On the My Overview page, select View Channel Lineup.
STEP 3: If the channel you’re trying to watch is not included in your package, select Change Package to make any changes.
Still seeing Error Code 721 on your TV screen? Try Solution 3.
STEP 1: Unplug your receiver’s power cord from the electrical outlet, wait 15 seconds, and plug it back in.
STEP 2: Press the Power button on the front panel of your receiver. Wait for your receiver to reboot.
STEP 3: Go to My Equipment to refresh your receiver again.
Still seeing Error Code 721 on your TV screen? Please call 800.531.5000 for assistance.