user configured DNS in Telus not working - disconnect then starts working

Hi

I am experiencing an issue with DNS.  After few weeks the DNS stop working; quick fix is I can log into the Telus Hub - go to Network Status Press Disconnect and then Reconnect - that fixes the issue (see info after the ping).  However I am not using Telus default DNS.  Does anyone know why DNS will stop to work after a week or so?  There is DNS flush on this router or any way to get any diagnostics or logs.  Any suggestions to how to debug this issue?

Also I included ping information - this is how I am narrowing this down to DNS issue.

C:\Users\raghb>ping yahoo.ca
Ping request could not find host yahoo.ca. Please check the name and try again.

C:\Users\raghb>ping 1.1.1.1

Pinging 1.1.1.1 with 32 bytes of data:
Reply from 1.1.1.1: bytes=32 time=6ms TTL=60
Reply from 1.1.1.1: bytes=32 time=6ms TTL=60
Reply from 1.1.1.1: bytes=32 time=7ms TTL=60
Reply from 1.1.1.1: bytes=32 time=5ms TTL=60

Ping statistics for 1.1.1.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 5ms, Maximum = 7ms, Average = 6ms

C:\Users\raghb>ping 1.1.1.1

Pinging 1.1.1.1 with 32 bytes of data:
Reply from 1.1.1.1: bytes=32 time=6ms TTL=60
Reply from 1.1.1.1: bytes=32 time=6ms TTL=60
Reply from 1.1.1.1: bytes=32 time=6ms TTL=60
Reply from 1.1.1.1: bytes=32 time=6ms TTL=60

Ping statistics for 1.1.1.1:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 6ms, Maximum = 6ms, Average = 6ms

<After disconnecting and reconnecting>

C:\Users\raghb>ping yahoo.ca

Pinging yahoo.ca [13.248.158.7] with 32 bytes of data:
Reply from 13.248.158.7: bytes=32 time=5ms TTL=250
Reply from 13.248.158.7: bytes=32 time=6ms TTL=250
Reply from 13.248.158.7: bytes=32 time=5ms TTL=250
Reply from 13.248.158.7: bytes=32 time=7ms TTL=250

Ping statistics for 13.248.158.7:
Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
Approximate round trip times in milli-seconds:
Minimum = 5ms, Maximum = 7ms, Average = 5ms

C:\Users\raghb>