Good day,
Cleaning the coils on a Sub Zero should be a routine procedure.
At least once a year.
Unfortunately the depth, fin design and overall layout of the Sub Zero machines does not lend itself to vacuuming.
The coils, to be cleaned properly must be blown out, from both ends.
Service techs carry nitrogen tanks or air under pressure with a hose to do the job.
If you do not have access to one of these devices, a quality push/pull shop vac with a crevice tool and some patience will do the job.
It's ugly and messy but there is no other way to do it properly.

It should be done as soon as possible, and if it produces no results on frig temperature a service tech qualified on Sub Zero should be called since it could easily be a serious problem.