Use this only as fallback
Default flow is one-click Connect PayPal from the payments workspace.
Use manual merchant ID only when callback auto-resolution still cannot return merchant identity after retry.
Keep this path secondary so setup stays low-friction for most sellers.
Where to find merchant ID
In PayPal Business, open Account Settings then API access or business account profile details depending on UI version.
Locate the merchant identifier shown as Merchant ID, Payer ID, or PayPal Merchant Account ID.
Copy the 13-character uppercase alphanumeric value and paste it in the manual fallback field in /dashboard/settings/payments.
After saving
Save the value in the fallback form, then set PayPal as the live provider if it should run paid checkout.
Run one full buyer-style test from storefront to confirm payment and post-checkout flow.
If manual save fails repeatedly, verify the seller account is a business account with active checkout capability.