Cronbach's Alpha

[sumah]

Hi. I want to calculate the Cronbach's Alpha for a 3-item 5-point Likert scale. I did so but I have a question.

1- I calculated Cronbach's Alpha and it was 0.852 but one variable seemed to reduce this value so I decided to remove it. photo below: 

 

2- Removing that item left me with 2 items/variables. The new Cronbach's Alpha is 0.943 .. this was already shown in the first table (first photo) but I wanted to run the code using the two items so I can create a new table just to show the difference. 

3- I ran the code and the output is shown in the photo below.

I understand that I can compute Cronbach's Alpha for two items as long as they are highly correlated and this condition is met.

My question: Is there an explanation as to why Cronbach's Alpha was not calculated and instead was shown as a missing value (second photo)?

[Ksharp]

In the second picture. there are only two variables ,when delete one of both ,you can't get Alpha (you can't calculate Alpha by only one variable).

[sumah]

oh i completely missed that. thank you so much.