If you move your question to the Products section you will get a lot more traction on this. This section is designed for help with the online community website. Poorly named and everyone does it, but most people just look there.
In reply to myself - I needed to create a Role that had API access rights as none of the default roles could access the API (didn't realise that was the case, assumed Admin would have access)
Now that's been added it seems to work.
Were you able to use Standard MarketoREST/API connector as part of Boomi , Did you use regular Rest Webservice call as we do for any other web url.
I am asking this since I had been asked to integrate the Merketo with Boomi, But I dont see much documentation on what would be the Key fields that needs to used for querying to extract the data when we use the Standard connector provided by Boomi. any help really appreciated.