After February 1st 2022 Apple will no longer support authentication using certificates. If a source is using certificates it will be noted in its definition label. You will need to reconnect these sources to continue downloading data.
Note that it might take up to 24 hours for your definition label to update.
To connect to Apple Search Ads you need to get some IDs from the Apple Search Ads UI.
Getting the different IDs
From the Search Ads UI, choose Account Settings > API. You will need to have the role API Account Read Only (API Account Manager will also work), however being Account Admin will not be enough. Since the user will have to have to remain in this role you may want to invite/create a new user for this purpose.
Copy the public key (including the BEGIN and END lines with the dashes) and paste into the Public Key field as seen in the picture below.
-----BEGIN PUBLIC KEY-----
-----END PUBLIC KEY-----
Click Save. A group of credentials displays as a code block above the public key field.
Using the IDs to connect to Funnel
Enter the clientId, teamId, and keyId into their respective boxes in the connect window.
At connect it's possible to select time zone the data will be fetched in. It could either be the Org time zone (default time zone) that is set by the user during account creation through the Apple Search Ads UI, or UTC.