701 invalid url response on image's external url of an email

[Joseph_Wood]

Hello everyone,

When I submit a REST POST request to update an email content section endpoint which has the external url property, the request fails with this error: Marketo API error (701): "invalid url". It only gives me that error on certain websites, most of the website works.

Not working: (https://via.placeholder.com/1280x640.jpg). 

I tried several different websites and most of them work, but some fail with that 701 error.

/rest/asset/v1/email/{id}/content/{htmlId}.json

Is there some kind of validation in the url property that is not documented or that I am not aware of?

Thanks,

[SanfordWhiteman]

What’s another one that does work?

[Joseph_Wood]

Working urls: https://placekitten.com/200/300

                         https://i.picsum.photos/id/237/200/300.jpg?hmac=TmmQSbShHz9CdQm0NkEjx1Dyh_Y984R9LpNrpvH2D_U

[SanfordWhiteman]

As off-kilter as it is, I wonder if the difference is the presence of CORS headers (in the ones that work).

This doesn’t make sense from a technical standpoint, as images are not blocked if Access-Control-Allow-Origin isn’t sent. But it does distinguish the 2 that work from the 1 that doesn’t.