my old code keep getting mysqli_fetch_array error in newer device [duplicate]

i was building a web based application using my old code from my previous work in my older laptop on a newer laptop, but somehow it didn’t work in my newer laptop, i tested the code on my older laptop and it still works fine.

error message:

Warning: mysqli_fetch_array() expects parameter 1 to be mysqli_result, bool given in D:XAMPPhtdocsrpl2sppstafdatastafread.php on line 32

the line in question:

$staf=$mysqli->query("SELECT * FROM staf ORDER BY id_staf");
$no=0;
while($stf=mysqli_fetch_array($staf)){

i apologize for my bad english,