What is your anti-virus software?

I'm not sure. How would I figure that out?

Okay, googled that and it appears I do not have one. See screenshot attached.

For Windows 7, I would recommend MS Security Essentials, and after setup, add the TB profile folder as an Exclusion in the MS SE settings. The profile location is shown in Help/Troubleshooting, about:profiles. The error might also appear if you have a VPN. The smtp settings are correct.

Consider upgrading to W10, which in many cases can be done as a free upgrade.

Thanks for the suggestions. I aded MS Security Essentials. Do I add the root directory folder, the local directory folder or both as an Exclusion in the MS SE settings.? I don't have a VPN . Although the upgrade to Windows 10 is 'free', when I discussed this with Microsoft a few months ago, they did indicate there would be a monthly subscription cost. Also, my PC is from 2013 and I'm afraid if I 'upgrade' to Windows 10, it will explode!  :-)

Thanks again.

Add the Root Directory, the one in AppData/Roaming.

I've never heard of W7 to W10 requiring a subscription fee. There could be one to receive updates to W7, which is otherwise at the end-of-life stage.

https://www.zdnet.com/article/heres-how-you-can-still-get-a-free-windows-10-upgrade/

I have a Core 2 Duo from 2006 that runs W10, initially with just 2 GB RAM, but now 4 GB.

I added that folder to the exception list.

As for MS 10, that's a long list of things to do, most of which I have *no* idea how to accomplish. I could probably bumble my way through it if I had 10-20 hours to spare to figure out how to get through all those steps. Perhaps I can find someone with more tech savvy to help me do it!

Thanks for your help.