'Postman with Pre-request Scripts: "Error: Parse Error: Header overflow"

I was having this problem only when running requests for a local application with some Pre-request Scripts:

Error: Parse Error: Header overflow

The Postman version was: v7.25.0.

PS: For the same request for my server application, I wasn't received any errors.

Solution 1:^[1]

I'm using a MacOS Catalina 10.15.5 with a rails 6.0.3.1 and puma 4.3.5 on localhost and nginx on the server.

The problem for me was the scout_apm that includes a huge header. I ended up by removing this using SCOUT_DEV_TRACE=false

The solution for this problem just to upgrade Postman version:

Other important information about my current environment:

One more option is to set environment variable and launch Postman again:
NODE_OPTIONS=--max-http-header-size=16384

In case your header is really huge, maybe you want to even use:
NODE_OPTIONS=--max-http-header-size=65536

Source:
https://github.com/postmanlabs/postman-app-support/issues/8656

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