PayPal plugin does't work on iOS when Capacitor is used for build

Paypal works fine only when using Cordova. But when I used the Capacitor it doesn’t work on iOs. I understand that it is not on the Ionic side. But I just want to inform you that
https://github.com/paypal/PayPal-Cordova-Plugin plugin works correctly only with Cordova.

This guide https://ionicframework.com/docs/native/paypal works only using Cordova. I created empty apps (only with PayPal plugin) using both Cordova and Capacitor and tested it with the latest library versions.

Error body from PayPal pop-up:
Invalid merchant
Payments to this merchant are not allowed (invalid clientId)

Error from console:
PayPal SDK: Request has failed with error: invalid_client - System error (invalid_client). Please try again later. (401) | PayPal Debug-ID: 61c53ad41d07b [mock, PayPal iOS SDK 2.17.0] | Details: ( { “error_description” = “Client Authentication failed”; } ).

The clientId is correct from the correct production environment and works only on Android using Capacitor and on both platforms using Cordova.