Bug: API Returns Invalid API Key

[JarrydLong]

Based on this topic: https://www.paidmembershipspro.com/forums/topic/get-response-add-on-doesnt-recognise-api-key/

Steps to Replicate:

1. Install the Get Response add-on
2. Navigate to the 'PMPro GetResponse' settings page
3. Add in your API Key and hit 'Save'
4. An error Sorry, but GetResponse was unable to verify your API key. Please try entering your API key again. will pop up

Expected Behavior:

• The API key should validate as expected, and the relevant campaigns will show up on the settings page

Further Debugging

1. After debugging the API request and the ping we make, a NULL value is returned
2. The API Wrapper we're using appears to be abandoned (https://github.com/GetResponse/getresponse-api-php)
3. We should probably look at changing over to the newly supported SDK (https://github.com/GetResponse/sdk-php)

Environment:

• WordPress 5.4
• PMPro 2.2.3
• PMPro GetResponse 0.5
• Tested on both local and live environments