URL exists but Flowpaper doesn’t load it

Hi!
I’m having this issue with Flowpaper plugin where the url works and shows the pdf, but doesn’t work with the pdf viewer.
It all worked fine on dev environment, but it broke after migration.
I have tried deleting and reinstalling the plugin and deleting and uploading new pdf. Also, I have tried updating the path to file, the plugin is up to date.
Still doesn’t work and I can’t figure out why.

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