Error after deployment - has been blocked by CORS policy

Hi ,
I deployed before 2 days: 2 fullstack project using node.js and MongoDB.
Until yesterday, everything be fine and the websites worked.
Today , I gets the same error in 2 projects…
Anyone knows how to solves it ??

Links to the projects:

Hi there,

Thanks for reaching out.

If you’re making cross-domain requests in the client, you’ll need to configure CORS. The backend will need to include the Access-Control-Allow-Origin header as the error shows. This header would list the domains that are permitted to make requests (i.e. the front-end domain).

In Node, the cors package may be one way to help you set this up.

Kind regards


Thank you for your ans.
I did this …
you mean this?

We’re not able to support your code, you would need to test this out yourself.

However, one thing to note is that wildcard origins likely won’t work if you’re passing credentials.


I have had the backend of my application deployed on Render for more than two weeks. Yesterday morning it was working and then yesterday evening I started to get a CORs error in my console log? I didn’t push anything during that time?

I’m not currently aware of any changes on our side that would affect CORS configuration, but I’m happy to look into this further, if you can provide some more details.

Please include as much detail as possible, e.g. service name/ID, URLs, response headers from the endpoint with CORS issues, times when the behavior changed (with timezone), reproduction steps, OS/browser versions, etc. If you don’t want to share these details on the community site, feel free to open a ticket at



Hi, I’m having the same issues as well. Something affecting CORS even though expressjs configs are set correctly.

Hi Ram,

As I mentioned in my last comment above, if any of you experiencing this issue can provide some specific examples/details we can look into it further.

“Me too” posts without any detail don’t really help us move forward in investigating the issue.



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