No signal & http: 12002 timeout on Blue iris

[cuem]

Hi all! Pls help me!
- i 've 13 Amcrest camera (model: 721s, 841, 943). i installed Blue iris Ver 4 ----> Only Amcrest 721s view ok on Blue iris, another not view (not show in Blue iris, note: No signal, HTTP: 12002 Timeout). I DON'T KNOW? WHY?
- But, all camera NOT show in Blue iris with note: No signal & HTTP: 12002 Timeout, i can show to direct by Chrome or IE or Firefox it ok. (EX: trang...ddns.net:1041 ---> it OK).
Tks!