DNS doesn't resolve certain sites today

I have an Xfinity gateway, so its DNS servers are whatever they are (75.75.75.75 and 75.75.76.76).  I can't change them.

Today I noticed that the URL to my bank doesn't resolve, i.e. I get a DNS error.  Pretty much everything else does.  Go figure.

When I log on to my job's corporate VPN (thus bypassing the Comcast DNS servers), the host resolves just fine, so the host is up, the domain hasn't expired, etc. etc.  From the standpoint of my network, the bank's hostname is unresolvable.

What options do I have to fix this problem if it doesn't magically go away soon?  Is this a "reboot and everything will be fine mysteriously" situation? 🙂