Quicken 2007: Can no longer connect to Bill Pay

Anyone else still using Quicken 2007? I am, and want to do continue to do so as long as possible. I briefly tried 2017, and whatta mess. But that's not why I'm writing now.

I use Quicken Bill Pay to pay bills within the software. No problems until last week, when I started getting an "Error 260" (cannot connect: Contact your financial institution). I also have Quicken installed on my laptop, and using the same data file and same software, Quicken Bill Pay still works.

So it's not a matter of Quicken Bill Pay shutting down for 2007 users, as I originally thought.

I called Quicken Bill Pay. (Quicken no longer provides support to Quicken 2007 users, but Quicken Bill Pay DOES.) However, Quicken Bill Pay rep could not figure out what went wrong.

I tried: transferring over the data file from my laptop, and using that. No luck. I re-installed the program. No luck. I transferred over the data file from my laptop again. No luck. I deleted the "p list" file. No luck.

I'm fortunate that the software works on m laptop. But I don't like having decades of my financial information on the laptop, which I carry with me when I travel, etc. Also, the screen is too small to comfortably work on it. I want to get it working on my desktop again. What else can I do?

By the way, my desktop is 10.10.5 (Yosemite). I run El Capitan on my laptop. Both are older machines, in need to replacing. My desire to hold on to Quicken is one reason I am reluctant to get new computers.

Any ideas out there?