Web Bill Pay E-Billing Problems

I routinely use e-billing through my bank's (credit union) web site to manage my bills.  AT&T, like many companies and providers, offer e-billing which links to my banking web bill pay interface.  Then rather than logging onto the AT&T website, and managing auto-pay there, and the same with every other company I pay monthly bills to, I can manage all through my banking website.

The problem I am having with AT&T, is that I set up the web bill pay, it confirms the bill and I start to receive e-bills on my banks website.  Then after approximately 1-2 months, I get an email from my bank that AT&T has canceled by e-bils:

You won't receive eBills from AT&T U-verse

Hello, AT&T U-verse canceled your eBills for *****xxxx. You will receive paper bills through the mail from AT&T U-verse. ...

I go back in and my bank says that e-bills are available for that account, then I go back through the process to set them all up again.  What makes it more inconvenient, I have to wait for a billing cycle to set up auto-pay so my bank starts sending payments in response to the bill.

I have never had this problem with any other biller, I've been having the issue with AT&T 2 years or longer.  When it first happened, I called AT&T customer service, they don't seem to have any department that details with e-billing through bank websites.  They all point to their own online billing, or that it's a bank problem.  I contact my bank, they clearly state it is AT&T which is canceling the bills.

Is anyone having a similar issue or have any idea how to solve the problem?!!!