Randy, you know how gray my beard is!
You have the right attitude! It's sometimes frustrating when you know there are fish that can likely be caught, but you can't seem to find the correct combination to make it happen. IMO, those are the types of days that we can learn from the most. The days of easy fishing, when most things we try will work, can give us a bit of too much confidence, and when the tough days happen, brings us back down to the reality of what fishing can often be.
There could have been several possible answers to what you encountered. Personally, I think I would have gone bigger with the fly, particularly if the water was a bit muddy or stained, perhaps flashier, and heavier. This is where having a variety of flies on hand can come into play. The usual flies that work when conditions are ideal or close to it, may not be what you need when the situation becomes more extreme.
If you recall, when we were looking at the flies in the boxes I showed you, I like variety!
Tippets & leaders are easy to adjust, but even having that corrected if you can't get the fly down to where it needs to be, you still haven't solved the entire problem.
Next time we meet, I'll try to put together a few flies that may fit the conditions you encountered a bit better & perhaps will aid you next time.