Error only on some posts

Hi there,

I have this error coming up on my FB page:

“errors”:[“code”:3,”msg”:”Authentication failed. Either _user_id is not set or invalid.”],”warnings”:[],”data”:null,”page”:”current”:1,”total”:1

It actually occurs only when the autoposter sends to the social network the posts written normally on WordPress. I say normally because the most of my posts are imported with WP All Import.

Those imported get published fine, the ones the I wrote on the traditional way give this error.

Thanks in advance.

Best regards