Caution provisional headers are shown in all browsers only on local machine

Question

I am developing a page. now since today in the morning, i cannot send ajax post calls, and getting this error:

Caution provisional headers are shown

even if i disable adblock and put all necessary crsf tokens in posts, i am still not able to do posts as ajax..

yesterday i was able to do all these calls, i tried now by deleting sessions and cookies in browser but nothing changes.. still having the same problem.

but in my live page, having the same code, it is working without any problems..

what should i do now?

Answer 1

It seems to be related to some Chrome extension which is blocking the request. To debug, you can try incognito mode or --disable-extensions option from command line.

Another debug trick is shared on "CAUTION: provisional headers are shown" in Chrome debugger:

The way I found about the extension that was blocking my resource was through the chrome://net-internals tool in Chrome. Just type that in the address bar and hit enter. Then open the page that is showing problems. Then go back to net-internals, click on events (###) and use the textfield to find the event related to your resource (use parts of the URL). Finally, click on it and see if the info shown tells you something.