Customer Claim code

Issuing this example command for one of my newly minted customers errors:

curl -u my-client1-id:myclienttoken -d grant_type=client_credentials -d scope=customer=customer@email.com https://api.particle.io/oauth/token

give the following error:
{
“error”: “invalid_scope”,
“error_description”: “Requested customer scope doesn’t exist”

Also
for parameter passing purposes how do I pass "scope=customer=customer@email.com" in a form? Is the query name “scope=customer” and then the value "customer@email.com"

thank you