@Lythman 

What is the wire that was missing from the second switch?

@Tony   I hope this pic helps. I'm an Network & Server Admin for my career. But somehow home electrical out smarts me all the time.

@Lythman 

Do you have a before picture?

@Tony @B.Will 

Here is the downstairs box and wires. There are two switches a lot of extra wires.

The only the wires connected to the downstairs switch were the three wrapped together on left.

Downstairs switch before

Downstairs switch after

Upstairs Switch Before  --- This only shows the switch after the wires were cut, but you can see only three wires were connected.

Upstairs switch after   --- No additional black “Traveler” wire

I don’t know if you or someone can help with my problem. Any assistance would be greatly appreciated.

@Lythman 

Here is a FAQ that gives some helpful information: https://www.tp-link.com/us/support/faq/2009/

The setup that you are working with mainly with the four wires seems to be that your outlets may be 4 way outlets.

@Tony 

Tony, 

Thanks, I've been to that FAQ page before, however I think I might see I went wrong or can do a (SAFE) work around. I will let you know what happens.

Kris

P.S. If I don't respond for a few weeks I either burned my fingers really bad or burned down my house. LOL

Just joking... I know, especially on something you don't know, SAFETY FIRST. 

The above sentence is directed to future users who might read this.

@Lythman 

Very good point.

@Lythman 

Put the upstairs dumb switch back in, you only need 1 of the 210 switches for it to work.

On the downstairs 210 using the original 3 wires, put the white and red to the travelers, Black to the common.

White from the switch goes to the group of white wires in the box that has the yellow wirenut.

Sorry for the delay getting back to you.

@B.Will 

Thanks for the idea and assistance. The only problem is, I am anal retentive, I like having the switches in the correct position.  In other words, if the lights are on, the switch (switches) are both up, if off then down. Or in the case of (most) smart switches just in one position. So putting a "dumb" switch back is not an option for me. I know, I like to make things harder on myself then they have to be.

However, I also paid for these switches to work properly as described on the website and information. Also, the step by step instructions on the app are not exactly for the HS210, probably the 200 or another previous model. Another thing, too many of these companies rely on auto translate software vs. proper localization. So, the instructions aren't always clear. They should at least have it re-written (localized) to English by professionals, hopefully that know electrical. With the amount of units they claim to sell, it would cost the consumer probably $2 per unit extra. 

Sorry rant done. 

From what you said, could I just do the same thing on both units "put the white and red to the travelers, Black to the common." That is what I was going to try later today. Well the one I was hoping on the most.

Thanks @B.Will 

Any other ideas from anyone else still welcome also.

@Lythman 

I did not see a picture of what wires are in the upstairs box, so I don't know if there is a neutral up there.

I assumed not, that why I said to only install one 210.