PayPal Express setup


When I Click “Pay Now” while looking at an invoice, I’m getting the “Security header is not valid”. My API username and password is correct, so I’m looking at the signature. The credentials that I got from PayPal include a private key and a certificate code. Which one qualifies as the Signature under the Merchant Account setting? I’ve tried both, and even together, but I’m still getting the error. I’ve also looked for unwanted spaces and hidden characters, which seems to be the popular answer for others having similar problems.


So I’ve discovered that in order to get a proper signature, I had to first remove the certificate, and reapply for a signature instead. It seems PayPal didn’t want me having both.

Still getting the error, but now I know the the signature is not he same as either the key or the certificate.

Its because you have it in test mode, when you take it off of test mode PayPal will function correctly.

I did check for that, and Test mode is off.

I reinstalled the program via Softaculous going with the defaults, and now it works fine. I had attempted at installing it under a subdomain, making the appropriate adjustments in the .htaccess file and such. Everything else was working, so perhaps there was some unknown config option in some file that I wasn’t tending to.

Anyway, problem resovled :smile:

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