Azure credit and Azure Portal successful, but login to Startups Portal fails

Hello
I have successfully registered for the Microsoft for Startups basic offering using a new Microsoft Account [1].
Using my Microsoft account, I can log into the Azure Portal successfully and can see my "Azure for Startups" subscription with free credit.

However, when I try to log into the Microsoft for Startups Portal using LinkedIn I see error "No user found. Please sign up or try a different LinkedIn account".

Initially I though this is because my Primary LinkedIn email address is not the same as the email address of my Microsoft Account [1]
In LinkedIn, I changed my Primary email address to my Microsoft Account email address.
Again I tried again to log into the Microsoft for Startups Portal using LinkedIn - same error as before.
I created a new LinkedIn account for using my new Microsoft Account email address - same error as before.

Please can someone help?