Computer time sync

I've been digging into the synching of time via internet servers because I get trade markers on my chart that are way off the bar that the trade was executed on.

I've tried all the suggestions in this thread but am getting random results.
I've tried:

1. Dimension 4
2. Windows automatic updates
3. Manual syncing

The results are that some days its no problem and time is updated immediately and other days it just errors constantly. Some suggested it was a firewall issue so I pinged the server simultaneously while updating time. The ping went through but the time update produced an error.

What is interesting is Dimension 4 gives you a history of its synching operation. This picture shows that there are gaps in days where time updates do not work. Does anyone have any information on this? It just seems so strange.

regards
taddypole...