The same thing happens to me. From what I remember they changed payment processors at some point and I think it is what is causing the issue. I'm not sure if there is some work around to purchase a renewal if you are on an old version but if someone knows please share.
BI 5.4.7.8
Click Upgrade/renew in settings, click the "Extended support and maintenance ($29.95 annually)" link:
View attachment 233255
Redirects to:
View attachment 233256
I'm guessing we would need to purchase an upgrade from here for $50:
Video Security and Webcam Software
www.sendowl.com