docker build --ssh default doesn't work on Ubuntu

I am trying to run following docker build command on Ubuntu 20.04.2 LTS

docker build --ssh default -t dev-build:$BUILD_NUMBER .

and have following command for installing private package using composer in Dockerfile

RUN --mount=type=ssh composer install

But its failing pass the SSH key

I am on Docker version 26.1.4, build 5650f9bSame command works fine on Macbook.

Any help on this what I am missing here ?