Email content has "null" instead of the name

Canvas has an email template set up and it should start with Hi FIRSTNAME. It worked correctly for my signups when I tested it but someone got “Hello null” instead of the name when signing up with Google. Why it might be? Is it something related to the API connector? - the only reason I was able to find for this specific case, however not clear what exactly should be added or removed.

The workflow to save the First and Last name also exists but they still don’t get saved (not always).

Thank you

Difficult to suggest possible fixes without a more detail look at the flow

Here is the flow:

I realized that the workflow that I had for it actually didn’t work - removed it but can’t understand how to target the first and last name, and profile picture of a social media account. For email I target inputs but there are no inputs here. Please advise. Thank you!