How do I resolve the following errors that are appearing on my web pages?

Warning: preg_match(): Compilation failed: nothing to repeat at offset 1 in /home/connec94/public_html/wp-includes/class-wp.php on line 207

Warning: preg_match(): Compilation failed: nothing to repeat at offset 1 in /home/connec94/public_html/wp-includes/class-wp.php on line 208

Warning: Invalid argument supplied for foreach() in /home/connec94/public_html/wp-content/plugins/popover/inc/class-popup-public.php on line 190