Step 1: How to get PayPal App ID.
Step 2: How to get “Paypal API”
Go to profile-> My selling tools, click the button “update” of the API Access like this image
In the next screen, Click in to the button “View API Signature” (if you have not created any api, just create new API signature)
1) The X-PAYPAL-APPLICATION-ID header contains an invalid value
Some reasons: You are using a sandbox APP ID or not set correctly the App ID of this email. Kindly follows step 1 to get the exact APP ID
2) Authentication failed. API credentials are incorrect
Kindly follow step 2 to set correctly the API of the Escrow.
3) User is not allowed to perform this action
+ The error is because your Adaptive Payment application is not approved for Chain Payments and you are trying to execute Chain Payments API. Also It might be caused by the status of your APP is not approved(is pending or Approve conditionally).
+ It is also possible when your business/premier account is not Verified. in order to verify your account you must add a credit card or a bank account into your PayPal account.
+ For more detail, you can use the link at the end of this post to check your PayPal account status, upon getting the status of your paypal account, you can solve yourself or contact to PayPal to solve the problem.
4) Account Account not found. Unilateral receiver not allowed in chained payment is restricted
For Adaptive Chained Payments, all receivers must have an active and verified Personal, Premier or Business PayPal account.
Note: The application owner must have a PayPal Business account
5) Account account not found. unilateral receiver not allowed in chained payment is restricted
Note: Please make sure the paypal email of freelancer is not empty
5.1) That is usually caused by receiver’s email address that is unconfirmed. Please make sure the freelancer’s email is verified.( For chained payments receivers do NOT need Premier or Business PayPal accounts. They just need an active/verified PayPal account.). Also, please make sure the freelancer account is using a live paypal account(not sandbox).
6) Internal Error : You did not set APP ID in API section.