The problem has been resolved. It turned out to be related to the built-in Windows antivirus. For the experiment, I installed a free antivirus and checked again, and the issue reappeared. I have no idea why this problem occurs, but now I know how to fix it. In the free antivirus, I added the root folder of CC to the trusted ones, included them in the exclusion list, and added the folder and all CC executable files. I also did the same in the Windows firewall. And everything started working. More precisely, it started working only after restarting the system. But now everything is working fine.

Good of you to post the solution here. It may help others in the same situation.

Yes Inger! That's exactly why I wrote. The program is very good, just like all programs developed by CC. It seems to me that the developer has abandoned this program, and there is a logical explanation for this. Both SD and HTML Editor have built-in FTP functionality, so the need for the Direct FTP program disappears on its own. Therefore, both SD and HTML Editor are self-sufficient.

It would be great if the developer created a comprehensive SEO program, incorporating Website Insight, Sonar Coffee, and Cup Website Access Manager functionality, plus all the essential SEO developments. Then it would be a dream for any web enthusiast!

Such a program could shake the business of CMS developers. It's no secret that despite the undeniable advantages of HTML for SEO, many still stick to CMS engines purely for convenience, as there are plenty of plugins and modules developed for them.

Most importantly, may the developers have many years and inspiration ahead, so that they don't abandon SD and HTML Editor! It's a pity that I discovered them so late.