Paypal Checkout module payments are stuck at "payment pending"

[Furkann]

Hello, we are facing a seriously annoying problem.

When customers pay via PayPal, the payment is made smoothly and the invoice status is entered into the system as "payment pending". But the transaction is never completed and PayPal does not automatically send the transaction ID to whmcs. Therefore, we have to track and enter this manually. It becomes difficult to keep track of orders as they arrive, and since the invoices do not appear to be paid automatically, we have to confirm the orders manually.

We use the Paypal Checkout module.
In the IPN settings, we entered the URL as "https://yourdomain.com/" and activated it. (whmcs is installed in https://yourdomain.com/ directory)
Webhook as given in the documentation
We fixed it as "modules/gateways/callback/paypalwebhooks.php".

However, I am encountering the errors shown in the visual, and we are in a really difficult situation. It is one of the most terrible and inadequately documented modules I have ever seen and read in my life.

I would like to thank those who have helped and will help in advance.

[leemahoney3]

406 is because of an exception thrown in the callback file.

I notice you were originally hitting the paypal.php callback file, which then logged that the 'paypal' gateway isn't activated. This is correct.

When you updated the IPN to point to paypalwebhooks.php and get the 406, what's showing in your system logs? perhaps look in your php error log also and in the tblerrorlog database table (may need to switch error reporting on in WHMCS general settings)

[Furkann]

We noticed that there is an error caused by "Signature Verification Failed" in the Paypal module. Once the "Signature Verification Failed" error was resolved, this problem also disappeared, thank you.

[leemahoney3]

5 minutes ago, Furkann said:

We noticed that there is an error caused by "Signature Verification Failed" in the Paypal module. Once the "Signature Verification Failed" error was resolved, this problem also disappeared, thank you.

I had noticed your other thread which made me think the issue here was similar, glad it got sorted.