I'm trying to make a post request to a server but I keep getting this error

Content-Type is not allowed by Access-Control-Allow-Headers

I've tried adding content-type and access-control-allow-origin to the Access-Control-Allow-Headers at the backend but it still brings up the same error

Searched on Google and I couldn't find a working solution

Please do you know the solution

Let's see your code. It's a common error it should be easy to solve

install cors and use it as a middleware

app.use(cors()) will help you, use all you want during your development... but unsafe for production

for production, something more like below is sufficient.

https://i.imgur.com/2mJG5Uw.png

Then pass the delegate to it, like so
app.use(cors(corsOptionsDelegate))

QuoteJustOnce:
app.use(cors()) will help you, use all you want during your development... but unsafe for production

for production, something more like below is sufficient.

https://i.imgur.com/2mJG5Uw.png

Then pass the delegate to it, like so
app.use(cors(corsOptionsDelegate))

You forget to tell him at the top of his code before making any request