No blockage in my vacuum cleaner but it keeps shutting off during use using an electrolux oxygen

The ( so called ) Electrolux Oxygen is a Eureka vacuum cleaner in disquise. They have a reputation of failure after a year or two. This is primarily caused by cheap electronics that are used. Take it to your local vac repair shop for diagnosis. They can give you the price for repair and also show you some better products that are made somewhere other than China, that will work better and, cost less, and last longer.

The motor's overtemperature thermal shutoff is shutting down the motor. This is due to
undue load on the motor, from:
(a) bearings have lost lubrication and are about to seize up if you run the vacuum much more, or
(b) there is some resistance to turning the motor that has increased over time, possibly a loss
of lubrication around the beater bar, or turning the impeller.
Either way, finding the lubrication point that needs to be addressed will revive your dying vac.