Magento2 file could not be downloaded: Failed to open stream: Network is unreachable

The “http://repo.packagist.org/p/paypal/module-braintree-graph-ql%245690cb72028a8444b0f87c92557cb7e772f5e673c323118e1a18304afae1eb14.json” file could not be downloaded:
Failed to open stream: Network is unreachable

I am getting this error when running composer update cmd in Magento2.

I already tried by deleting the composer lock, vendor, clear cache etc..

Please help how to solve this