Hi Cryout Creations,
It seems that Force Regenerate Thumbnails Plug-In was last updated four (4) years ago!
It is marked as “Untested” with current WordPress versions.
When I ran it I had problems.
So I deleted it and looked for something else.
I found reGenerate Thumbnails Advanced by ShortPixel. It seems to work. Documentation is rather sketchy. There is a link to a documentation page, which helps some.
You might want to check if Pedro Elsner has abandoned Force Regenerate Thumbnails.
And you might want to recommend a different Plug-In…???
I know that plugin hasn’t been updated in some while, but last time I used it (several months ago) it worked fine with then’s WordPress version. I’ll do some more tests now and also look for an alternative plugin to suggest.