CORS header Access-Control-Allow-Origin missing some of the time

[publicsite]

Hi, some of the time the request works, and some of the time I get the following error. It's almost 50/50:

Cross-Origin Request Blocked: The Same Origin Policy disallows reading the remote resource at https://api.allorigins.win/json?url=https://myurl.org. (Reason: CORS header ‘Access-Control-Allow-Origin’ missing). Status code: 500

[Bizarrus]

I have the same issue.

[publicsite]

I'm not 100% sure but when I tried fetch API using javascript, rather than XML HttpRequest, the problem of intemittantly missing Access-Control-Allow-Origin header seemed to dissapear. Ie. the fetch API perhaps seemed to be better and not have this same problem. Unfortunately I can't test this further at the moment because I am now getting 502 upon request, for which I have filed another bug.