Zoom Webinar - Adding Participants Using The Same Browser

I had a webinar scheduled last night and not one person showed up. Here is my question... I created the webinar and I also registered all of the participants using the same browser(without deleting cookies, etc.). The reason being that the webinar registrants came from Facebook Leads so I registered each new lead manually to the Zoom webinar. Would there have been any technical issues in using my computer/same browser to add each new registrant? I am guessing no, but I just find it strange that not one person showed up. The one individual who did show up registered herself through her computer/browser.  Thoughts?? There may be other marketing related reasons as well like there was no charge for registering for the webinar, etc.