Pull fails on redeploy; network is unreachable

We had an issue last night and earlier today on one of our two nodes hosted on AWS. Redeploying a stack or service would fail with

Redeploying... laravel-1: Pre-pulling image tiigbgcloud/musikjakten:latest in 26a7cb62-411b-418a-9a93-0771714d26c5.node.dockerapp.io ERROR: laravel-1: Error while pulling image: Get https://index.docker.io/v1/repositories/tiigbgcloud/musikjakten/images: dial tcp: lookup index.docker.io on dial udp network is unreachable ERROR: Service Redeploy (autoredeploy on push) action on 'laravel' (using 'tiigbgcloud/musikjakten:latest') has failed

However, we could ssh into the node and run docker pull without any problems. Now a couple of hours later this issue has suddenly been resolved, but we feel it is important to know what caused this since it stopped our deployments for almost 24 hours.