Hi @behroooz,
What version of the plugin are you using at the moment?
I tried reproducing this on my website but the function seems to be working normally for me.
<?php
echo '<p><small>This post has been viewed a total of ' . wpp_get_views(get_the_ID()) . ' times - using wpp_get_views(get_the_ID())<br />';
echo 'This post has been viewed a total of ' . wpp_get_views(get_the_ID(), 'all') . ' times - using wpp_get_views(get_the_ID(), \'all\')<br />';
echo 'This post has been viewed a total of ' . wpp_get_views(get_the_ID(), ['range' => 'all']) . ' times - using wpp_get_views(get_the_ID(), [\'range\' => \'all\'])</small></p>';
?>

Any other thing I should try to reproduce the problem?
not working for me
I had this problem before, and I changed something in the database, and boom! problem solved
but I can not remember now what did I changed π
Long shot but give this a try and let me know if it fixes the issue for you. If not then I’ll need more details in order to be able to help out.
Thank you
with this solution problem solved