I found a couple of threads from 2017 about this, however they never resolved, and it was recommended to create a new thread, so here I am!
VNCViewer produces the following message, which flashes up every second or so. Interestingly about 1 attempt in 10 seems perfectly fine, which is odd, and probably therefore hard/annoying to track down, however I thought I'd post in case there were other solutions / known issues.
Thanks
