Beater brush does not rotate

There should be a rubber belt somewhere along that roller, probably in the middle, behind the bottom cover plate, Remove the plate. That belt may have just slipped off the motor shaft, but it may be broken.

The belt could possibly be installed in either of two ways. The motor shaft is not parallel to the beater bar (brushes), so the belt must twist to wrap around both the motor shaft and the beater bar. If it's twisted one direction, the beater bar will rotate the correct direction (as if drying to pull the vacuum forward). Twisted the wrong way, it'll rotate the opposite direction. Try it one way, then bump the power switch to verify that the brush is rotating the correct direction before putting the bottom cover plate back on.

This message generally means that the beater/brush bar is not turning. Try rotating the beater/brush bar manually to see if it can turn freely. If not, you will need to remove the beater/brush bar and ensure that it is clean; that the orange end caps on the brush are free of hair and dirt, and that the bar housing area is free of obstructions.

Note, when I said "beater/brush", it could be either/or, depending on whether you're using the "standard" beater bar, or the upgraded pet brush.

Not sure this is your foolproof solution to the problem, but you might give it a try to see if it solves your problem.
When the beater brush starts to bind up due to debris it retards the action of the cleaner, sometimes to the point of the belt breaking.
Remove the beater brush as if you were going to change the belt. Remove all debris and clean as best you can. Pay attention to the end pieces on each end of the beater brush. They will can clogged to the point to stopping the brush from rotating. Add some WD40 to the clips at the end of the beater brush and work in by twisting the clips while holding the beater brush. Once it seems to be free, reassemble and be sure the belt is on properly, you might want to consider replacing the belt.
If you find this solution to be of help I would appreciate a Thumbs Up. Good luck and be well. Paul

Sounds like the rubber drive band has not been replaced properly to drive the brush and/or the brush was not properly cleaned. You can find the manual here:
http://dl.owneriq.net/4/4d79dca8-65d8-4c46-a58a-a2fef1f89635.pdf

Sounds like the beater brush is frozen and won't turn. Remove the beater brush and clean off all debris, especially at both ends. You will find a square(?) piece at each end of the beater brush that holds it in place. This need to turn freely. Put a little WD40 on these where the center rod of the beater brush enters the small holders and turn by hand until they turn freely. Once this is done, assemble with new belt, making sure the belt is put on properly.

Sounds like a broken belt may have been pulled up into the machine. Plan on replacing the belt and cleaning the beater brush. Remove the beater brush and clean off all debris, especially at both ends. You will find a square(?) piece at each end of the beater brush that holds it in place. This need to turn freely. Put a little WD40 on these where the center rod of the beater brush enters the small holders and turn by hand until they turn freely. Once this is done, assemble with new belt if needed, making sure the belt is put on properly.

Most likely a problem with the drive belt or the beater brush. Either the drive belt is broken or the beater brush is frozen due to debris. If you can not turn the beater brush by hand, it should be removed and cleaned well. The ends of the beater brush that hold it into the vacuum should be lubricated with some WD40 and moved by hand until they are free. Once the turn freely, replace the beater brush. If the drive belt is broken or missing, it needs to be replaced.

Not knowing what type of vacuum you have does not make it easy. However, usually caused by a broken belt or the fact that the beater brush is bound up by debris either being on the beater or having accumulated at the ends of the beater where the brush is supposed to spin on the end plates. After checking the belt I would remove the beater brush, clean it very good and put some WD40 on the ends of the axle of the beater brush and make sure it spins freely on the holding plates.

If by roller you mean the beater brush that the belt is attached to, you might try taking the beater brush out of the unit and clean both ends. There should be some kind of plastic or rubber holders on each end of the beater brush. The brush itself is supported by these holders, but the brush needs to be able to rotate in the holders. Sometimes they get gummed up and need to be cleaned in order for the brush to turn freely. Clean them up, apply some WD40 and make sure the belt is properly attached. Hope this helps.

More likely it is the beater brush which is jammed and not turning. Turn the machine over and remove the bottom plate. Unhook the drive belt, then try to turn the beater brush--it is likely bound up with string, thread, and hair. Try turning the machine on once--if the motor spins and makes vacuum, it is probably ok. Remove the brush assembly and clean it of debris. Clean the end bearings with a Q tip and WD40 oil, then wipe clean with another Q tip. Oil the bearings with 3-1 or other light oil. Check the belt for a badly burned area--replace if necessary. Slide the new belt over the brush and motor shaft, then drop the brush with bearings into the case, and check rotation. If ok, replace the plate and test on your floor. Hope this helps!