Blog home page has canonical link that is incorrect. Do not see where to change this

As part of our website we have a wordpress blog in a subdirectory. I scanned our main site for broken links. The scan included the wordpress blog in the subdirectory. Some broken links showed up that have never been present before. The problem is that the otherblog has nothing whatsoever to do with our website--it is a separate property. We don't know how the value for the otherblog is getting in.

The html looks like this:

link rel=canonical href=https://www.otherblog.com/blog/
link rel=next href=https://www.otherblog.com/blog/page/2/

In addition to the canonical link, there is also a bogus next link. Where do these bogus settings come from?

Searching on wordpress canonical link is wrong and similar searches lead to pages that give instructions similar to the following generic steps:

1. Go to the page where the problem occurs.

2. In the Yoast advanced section, adjust the entry for canonical.

An example of such instructions are at https://yoast.com/help/canonical-urls-in-wordpress-seo/.

However this does not help for one of the following reasons:

1. The page in question is the site home page, and there is no way to go to that page in the admin section.

2. For pages not on the blog home page, the Yoast canonical field is empty, and does not have the bogus value in it.

So where is the bogus value coming from, and how does one correct it?

Again, we have not had this issue previously over a period of many years. So it seems odd to start overriding entries on certain pages. And such an override would be to the same page anyways, which is not needed.