I can't enable video calls. XHR Error pop-up

Settings -> Asterisk Sip Settings -> Chan SIP Settings -> Video Support->Enable ->Save->Apply
Then I get the error
Error: Did not receive valid response from server
XHR response code: 0 XHR responseText: undefined jQuery status: timeout

Then I use “amportal chown” and “amportal a r”, the error won’t go away, until
I Disable the video support
Please help.