(Email:adelerooke%40optusnet%2Ecom%2Eau%2Euat) error syncing: Upsert to Salesforce (WordPress user with ID of 12)

Object: Contact

Message:

Params: Array
(
[Email] => adelerooke@optusnet.com.au.uat
[FirstName] =>
[LastName] =>
)

Upsert key: Email

Upsert value: adelerooke%40optusnet%2Ecom%2Eau%2Euat