During our process of transitioning to a more robust DOI proxy service infrastructure, we introduced a bug which prevented users from resolving DOI links containing an encoded slash (%2F). Links with %2F encoding would have stopped working after 2018-07-02 15:30 UTC, and started working by 2018-07-03 08:40 UTC when a fix was successfully applied.
Transition to the new proxy service infrastructure upgrade is complete.