Failing to generate critical CSS – trailing slash on homepage?

I’ve been running into this error all day today. The details say unable to verify [page] and then just shows https://www.steamericas.com/ but the hyperlink points to https://www.steamericas.com/?jb-generate-critical-css=undefined which displays a blank page – nothing.

What I just realized is that https://www.steamericas.com/ redirects to https://www.steamericas.com (no trailing slash).

I’ve looked at my htaccess and see the trailing slash redirect
RewriteBase /

WP General Settings won’t let me change the site URL to have the trailing slash; after save it’s gone.

I have the Redirection plugin, but don’t see anything to address the homepage URL

Thanks for your prompt reply!

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