As you can see in following link . I was not able to build contract using latest rust nighly ( rustc 1.70.0-nightly (17c116721 2023-03-29)) toolchain.

ERROR: Loading of original wasm failed

I got the solution from git issues, here - https://github.com/paritytech/cargo-contract/issues/1058

But now when i am trying to deploy the contract on substrate node it is not responding.

  • Please elaborate on what you try to do, what you see, what was expected to happen and what is happening.
    – Simson
    Commented Apr 21, 2023 at 5:35

3 Answers 3


Kindly downgrade your nightly version. There is some issue in the new update of the nightly.


this is the output of 'rustup show' in my ubuntu machine. (1.69.0-nigthtly is the maximum for the time being.) enter image description here

I would advise for you to use rustup override.


Make sure to use 1.69 or lower with the current cargo contract v3. Will be addressed in v4 as far as I know

rustup default 1.69.0

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