Nope, although believe me I have thought about it, I have not implemented that because frankly people had not been asking for it and it is not super easy to do properly.
You are getting hit by the new "security" features Ken added in 6.0.3.0.
Really it is not very fair to call them security features, it is more like bot/crawler mitigation features.
Which web browser are you using? It could be sending a User-Agent header that
Blue Iris did not anticipate.
If there is anything in the "Host/s" field in your
Blue Iris Settings >
Webserver tab, that may also be limiting which requests Blue Iris is able to respond to. I think it should be empty by default. (the change log mentions this but erroneously says it is in
Settings/AI).