First of all, check your network connection stability.
If there is no problem with network connection try another solution; it may work:
On Linux
Execute the following in the command line before executing the Git command:
export GIT_TRACE_PACKET=1
export GIT_TRACE=1
export GIT_CURL_VERBOSE=1
On Windows
Execute the following in the command line before executing the Git command:
set GIT_TRACE_PACKET=1
set GIT_TRACE=1
set GIT_CURL_VERBOSE=1
In addition:
git config --global core.compression 0
git clone --depth 1 <repo_URI>
# cd to your newly created directory
git fetch --unshallow
git pull --all
For PowerShell users:
As kodybrown said in the comments:
$env:GIT_TRACE_PACKET=1
$env:GIT_TRACE=1
$env:GIT_CURL_VERBOSE=1