OK, marton_1 and carlwhat, I have done as you suggested:
First, I level set my Z-C. I removed all plugin files (I searched my entire Z-C for all "seo" and "usu" filenames and blew them out.) and by ensuring I had no trace of the plugin .htaccess rules in my live .htaccess. (had backed it up, before editing it)
I placed the plugin .htaccess rewrites at the end of my live .htaccess file.
I tested the site -- all worked without a hitch. Thus, marton_1's suggestion worked.
I then copied all plugin files to their appropriate folders. Retested site, all still fine (as expected, but providing full detail)
I then set Plugin debug log = true and enable alternate urls = true.
Again, testing site, I find all is fine. It continues to operate as before installation and activation.
However, I am seeing no difference in URLs. Its the same category and product format as before, i.e.
https://australianbakerycafe.com/ind...index&cPath=65
or
https://australianbakerycafe.com/ind...roducts_id=180
Carlwhat - direct entry of https://australianbakerycafe.com/pie-p-185 DOES, in fact, render the product, that the URL by way of site navigation to Steak and Onion Pie does,
https://australianbakerycafe.com/ind...roducts_id=185
But the . . . /pie-p-185 URL doesn't show up on my site. So I don't know how you came up with that URL for that pie.
In summary, the plugin is installed, .htaccess merged, activated, and my site is working fine (). But I do not see it rewriting any URLs.
http:\\australianbakery.com\Screenshot_20210217_143753.jpeg
Bookmarks