Just add a new line in your config/reverb.php to specify the location of your intermediate certificate:
'options' => [
'tls' => [
'local_cert' => env('SSL_CERTIFICATE_CER'),
'local_pk' => env('SSL_CERTIFICATE_KEY'),
'local_ca' => env('SSL_CERTIFICATE_CA'),
'verify_peer' => false,
],
],
The key is the line ‘local_ca’ => env(‘SSL_CERTIFICATE_CA’)