Zend certified PHP/Magento developer

on deploy: en_US/jquery/jstree/themes/classic/style.css” file can’t be read

I’m getting this error when I do:

"bin/magento setup:static-content:deploy -f"

but the website works fine, what does it mean?

In File.php line 151:
                                                                                                                                                                                                                                                                                                             
  The contents from the "/var/www/magento/pub/static/frontend/Mytheme/custom/en_US/jquery/jstree/themes/classic/style.css" file can't be read. Warning!file_get_contents(/var/www/magento/pub/static/frontend/Mytheme/custom/en_US/jquery/jstree/themes/classic/style.css): failed to open stream: No such file or directory