How do I fix frequent video buffeting and frozen images?

Your network connection is not able to sustain the stream rate and/or is dropping on you.

Check your WiFi AP are you close enough to it? Also check to see if others are also running WiFi AP's near you you maybe fighting for the same bands. Look at changing your band if you can.

If your connected over your cell service then the location of the nearest tower and the number of others connected to it can cause this as well. Talk with your cell provider for help. You may not be able to get anything better.

Check your wired network are others in your household fighting for bandwidth? Your network provider (cable or other) may not have provisioned the line correctly (very common) and/or your exceeding what you were provisioned. You may find a given time during the day is worse than another if so your provisioned allotment is not being met.

Lastly, things happen! the connection thru the Internet to Netflix's servers may not be able to sustain all of the people connected at the given time.