From the Strategy Monitor tab:

Data: {DataSet: 1 Minute scale, 20 symbols}
Range: 1 Week
Scale: 1 Minute

Action tab changes as below. There are few more messages but they are too fast to catch.

Action(1): Entering Intraday Thread
Action(2): Skip Update (not current): XXX (37)
Action(3): Update2: XXX=123, YYY=234..., ZZZ=456,
Action(4): Time's up!

At the same time, the same strategy with Fidelity data provider is working fine.
Restarting WLD doesn't fix the problem. So the issue persists.
Removing the extended hours bar by Market Manager doesn't help.

Having encountered an error message or an issue, please always check out these pages:

1. Known Errors
2. Open Issues

In particular, a "Skip Update (not current)" error suggests that your PC clock is set incorrectly, confusing the SM. Synchronize your PC clock. It's required for SM to function correctly.

I'm running WLP(Fidelity) and WLD(IQFeed) side-by-side on the same desktop and the same computer.
WLD is having trouble while WLP is running flawlessly. It cannot be PC clock.
In fact, I configured my computers to synchronize the clock every hour.

It might help troubleshooting if you "Enable logging for selected items" in SM and attach the strategy item's log. Thanks.

All right. I will send it in Ticket Center.

Looking into the log, those symbols with "Skip Update (not current)" have out of date timestamps on their data. Could it be that IQFeed data gets stuck for those symbols?

So it is due to IQFeed data is bad?
How to trouble shoot it?

My bad. Robert has identified it correctly: your symbols DIG, DUG etc. look very illiquid on 1-min bar scale. There can be no trades for many minutes in a row. It has nothing to do with IQFeed.

Yes, it is something to do with IQFeed because I did get bars with Fidelity at the same time.
I'm sure because I'm trading on both WLP(Fidelity) and WLD(IQFeed).

Is the IQFeed trial 15-min delayed data? Check it on a streaming chart.

No, it's not trial. I subscribe NYSE and NASDAQ realtime.