Failed docker build

I use a docker container for my ci-build. Sometime, like every 8th build or so I get the following error. What is the issue here? Is i because of the shared runners?

Pulling ci-build (microsoft/aspnetcore-build:1.0-1.1)...
1.0-1.1: Pulling from microsoft/aspnetcore-build
Digest: sha256:9bd8dc7dd62655396d6e7021c3cce97266750bdf6bf13b7da7754df1adbff383
Status: Downloaded newer image for microsoft/aspnetcore-build:1.0-1.1
Creating tridoo_ci-build_1

ERROR: for ci-build  HTTPConnectionPool(host='docker', port=2375): Read timed out. (read         timeout=60)
An HTTP request took too long to complete. Retry with --verbose to obtain debug information.
If you encounter this issue regularly because of slow network conditions, consider setting     COMPOSE_HTTP_TIMEOUT to a higher value (current value: 60).

Thanks for the support

Matt

The performance of shared running has deteriorated in the past few days. I wonder if there are not enough runners.