gpgkeys: key 1A4E8B7277C42E53DBA9C7B9BCAA30EA9C0D5763 can't be retrieved

Service 'magento2' failed to build: The command '/bin/sh -c set -xe; fetchDeps='wget'; apt-get update; apt-get install -y --no-install-recommends $fetchDeps; rm -rf /var/lib/apt/lists/*; mkdir -p /usr/src; cd /usr/src; wget -O php.tar.xz "$PHP_URL"; if [ -n "$PHP_SHA256" ]; then echo "$PHP_SHA256 *php.tar.xz" | sha256sum -c -; fi; if [ -n "$PHP_MD5" ]; then echo "$PHP_MD5 *php.tar.xz" | md5sum -c -; fi; if [ -n "$PHP_ASC_URL" ]; then wget -O php.tar.xz.asc "$PHP_ASC_URL"; export GNUPGHOME="$(mktemp -d)"; for key in $GPG_KEYS; do gpg --keyserver hkp://p80.pool.sks-keyservers.net:80 --recv-keys "$key"; done; gpg --batch --verify php.tar.xz.asc php.tar.xz; rm -r "$GNUPGHOME"; fi; apt-get purge -y --auto-remove $fetchDeps' returned a non-zero code: 2

[yosifkit]

That happens all the time. GPG servers are unstable (see related issues in docker-library/cassandra#131). We solve this for our travis builds and on the official build servers by using a man in the middle proxy (see #666).

You should be able to just pull the image rather than building it; otherwise you may need to retry a couple times or add a similar proxy.