redirecting from https to http

I’ve got a subsite on a multisite network with domain mapping

things were working fine under http

when using https://example.com – I was getting an insecure error warning with images not loading — not surprising as they were coming from insecure url

so I activated SSL Insecure Content Fixer

and what has happened is that https site now simply redirects to http — I can’t even test or find insecure content

I can’t figure out how to undo this. cleared caches, activated/deactivated/enabled the plugin, changed settings…

any ideas?

thanks