Fax using Ringcentral - Error: Authentication Service Denies Access

Situation
Error: Authentication Service Denies Access. I have double-checked the information for account access to Ringcentral. How do I go about trouble-shooting this?

OpenEMR Version
I’m using OpenEMR version 5.0.2(5)

Browser:
I’m using: Safari 14.0.3 (16610.4.3.1.4) running on AWS (Standard version)

Operating System
I’m using: AWS Ubuntu 16.04.7 LTS (GNU/Linux 4.15.0-1093-aws x86_64)

Logs

[Thu Feb 11 12:51:24.824671 2021] [php7:warn] [pid 4115] [client 67.60.83.139:50475] PHP Warning:  json_decode() expects parameter 1 to be string, array given in /var/www/localhost/htdocs/openemr/interface/modules/custom_modules/oe-module-faxsms/controllers/RCFaxClient.php on line 162, referer: https://xxxxxxxxxx.com/interface/modules/custom_modules/oe-module-faxsms/contact.php?isDocuments=false&isQueue=queue&file=/tmp/xxxxxxxx