Impossible to save changes in my website

EVerytime I try to save changes on my website, I get this error:*
Tried to use a non-existent or unowned file*

How can I verify which file is this or ow do I fix it?

Hey there,

Happy to help. Can you give us more info according to this guideline, please?

🔷 Guidelines - Ask your question the right way – and get the best answer faster!

Also, was this website formerly copied and shared or created out of a self-made template or duplicated?