I Don't Know how to use Get Clips Helix Api

API
19

When i Tried to use the Encoded Date Format in the Api , It Actually Worked

$ch = curl_init('https://api.twitch.tv/helix/clips?broadcaster_id=157527726&started_at=2020-03-01T18%3A42%3A52%2B01%3A00&ended_at=2020-03-08T18%3A42%3A52%2B01%3A00');

var
var1047×521 40.7 KB

However It’s Not working when using Variables like this :

$ch = curl_init('https://api.twitch.tv/helix/clips?broadcaster_id=157527726&started_at=' . $date3 . ' &ended_at= '.$date4);