Connecting from a local environment

[paulgoodfield]

I'm having an issue where I can connect successfully when testing from a live domain, but when testing on a local environment I always get the following error returned from the ET_Client class:

Unable to validate App Keys(ClientID/ClientSecret) provided.: Trying to access array offset on value of type null

The config settings are exactly the same on both environments. PHP versions slightly differ:

Local Env: 7.4.1
Live Env: 7.2.24

[ekateiva]

This is because of PHP 7.4
More details in #159