I have used the COUNTA function to count the number of non-blank cells.
However, it seems to be adding 1 to the total.
For example- one person on the spreedsheet had ALL blank cells in the
selected range- but shows a value of 1.
The formula I'm using is:
=COUNTA(C6,E6,G6,I6,K6,M6,O6,Q6,S6,U6,W6,Y6,AA6,AC 6,)
I have checked the contents of each cell and there is nothing in them.

I have checked all the other rows and they have all added 1 to the total
number.

What am I doing wrong?