Another Failed WAN DNS

I have pretty much the same issues as previous users.

WAN 1 is TW Roadrunner Business.
WAN 2 is a T1.

I get a FAILED WAN DNS on WAN1 almost weekly. Got TW out there to troubleshoot their modem and they replaced but I still have the same issues. I tried disconecting and reconnecting via the web interface to no avail. However, I can ping the modem interface (external) all day long. The only remedy is to reboot the Peplink Balance 20. Here are my unit details: Peplink Balance 20
5.3.12 build 1303

Please advise,

There are couple of options you can try. You can include public DNS in WAN1 Health Check and increase the Timeout and Health Retries value. You can also temporary change the Health Check from DNS Lookup to PING for testing and monitoring.

FYI, we have a new firmware released recently and is available for download. You may try to upgrade the firmware as well.