Error "JSON parameter needs to be valid JSON" in HTTP Request node (n8n.cloud, v1.91.3)

Hello!
I encountered the error “JSON parameter needs to be valid JSON” in the HTTP Request code on the cloud version n8n (v1.91.3).

What was he doing:

I use the expression (fx) in the JSON Body field.
I’ve tried both static and dynamic JSON (with and without variables).
I’ve tried single-line and multi-line JSON.
Recreated the field and the entire node.
I cleared the browser cache and tried another browser.
The error occurs even with valid JSON validated through JSONLint.
Screenshots and an example of an expression:
(insert a screenshot and a JSON example)

Please help me figure out if it is possible to fix this or is it a bug of the platform?

1 Like

See if the technique described in this post helps.

Hi @luchinin78

Did you try using JSON.stringify()?

Also, please attach the JSON Body to help reproduce the issue…