Based on Shamim’s recommendation (after some troubleshooting with him, great support by the way!). Because of the web-server timing out trying to send to so many recipients (over 100) – he recommended i installed a SMTP plugin to do the sending instead. I installed “Easy WP SMTP” to handle the sending out. I happy to say that, at the moment, this has resolved the timing out issue. I also upgraded to the latest version as of posting this (8.3). I will continue to test.

Thanks to Shamim for his time and effort in finding a solution!