Google structured data testing tool finding errors in squarespace site

Hi there, Googles structured data testing tool is finding 1 error and 2 warnings on my blog pages. Can you explain how i can resolve them please?

Error: url
A value for the url field is required.

Warning: dateModified
The dateModified field is recommended. Please provide a value if available.

Warning: mainEntityOfPage
The mainEntityOfPage field is recommended. Please provide a value if available.

Many thanks,

Ben

Any update here?

This is still the case.