Euonymus fortunei has enough water but can't overcome the extreme temperatures to protect itself from Euonymus Scale. And, the poor thing has a bad case.
The University of Kentucky Ag site has a good summary and advice for treatments.
Since I won't spray poisons during butterfly season, I'll cut it back to the trunk and do harsh water treatments to remove as much as possible until I can do more in early winter.
It can become invasive (Invasive.org) in some areas such as PA - also zone 7, but it has not in our yarden.
Spellchecker has some amusing alternative choices for Euonymus ;-)