There are different reasons you could get a #N/A! error with the VLOOKUP function, we will put in a scenario of employee list, which looks like this:

employee list

1. Double click on the #N/A! error, copy the whole VLOOKUP formula except the = symbol, and then delete the copied formula.

double click error

2. On the same cell with = symbol (1), type IF(ISNA(Paste the formula with CTRL + V));"";CTRL + V again, and close it with ")" (2).

formula

In this example formula is: =IF(ISNA(VLOOKUP(A6,A8:E17,2,FALSE)),"",VLOOKUP(A6,A8:E17,2,FALSE))

Note: Repeat step 1 & 2 on all the #N/A! errors.

Further reading: 
Showing formula calculation steps
How to create many to many lookup?