I am having the same issue this morning. Worked fine all day yesterday, tried to bring up camera today from iPhone and got the blocking error.
Just spent an hour trying everything, including forwarding all kinds of udp ports on my router with no luck. I had changed NOTHING since yesterday when all worked fine.
Glad to see these messages here, wish I would have seen them before I wasted an hour!
Also rebooted everything this morning also, and no luck.