[ERROR] In modules/gateways/btcpay/createinvoice.php: Invoice error: 'invalid json:

[LastWoWProject]

I just installed btc pay server and downloaded whmcs modules from https://github.com/btcpayserver/whmcs-plugin

I have uploaded the module in gateways and i added my api key and URI to your BTCPay server ( wich i am guesing is my btcserver.domain.com ? ) Is what i did, i placed an order on my whmcs portal and i got the following error

//modules/gateways/btcpay/createinvoice.php

[ERROR] In modules/gateways/btcpay/createinvoice.php: Invalid invoice id #0
[ERROR] In modules/gateways/btcpay/createinvoice.php: Invoice error: 'invalid json:
400 Bad Request
The plain HTTP request was sent to HTTPS port
nginx
'
Any ideeas please?

Thank You

[votkon]

+1 on this one.
Just got the same error:
[ERROR] In modules/gateways/btcpay/createinvoice.php: Invoice error: 'invalid json:
400 Bad Request
The plain HTTP request was sent to HTTPS port
nginx
'
Running with WHMCS 7.10.3
Will post an update here if my investigation will bear any fruit...

[votkon]

ok, I think I solved this one:

In your BTCPay server payment gateway settings in WHMCS ensure that you have not forgotten to put "https://" in the "URI to your BTCPay server" field.
It looks like it is trying to send data to HTTP by default, which is pretty weird in 2024 imho.

I've also updated and restarted the server, but it feels like it's not related to this issue, as it's "the plain HTTP request was sent to HTTPS port"

Cheers