I am using WordPress 4.9.7

in the error log:

[06-Oct-2018 04:28:27 UTC] PHP Warning: require_once(): open_basedir restriction in effect. File(/volume1/@appstore/PEAR/PEAR.php) is not within the allowed path(s): (/var/services/web:/tmp:/var/services/tmp) in /volume1/web/wordpress/wp-content/plugins/front-end-pm-pro/pro/fep-email-parser/mimeDecode.php on line 65
[06-Oct-2018 04:28:27 UTC] PHP Warning: require_once(/volume1/@appstore/PEAR/PEAR.php): failed to open stream: Operation not permitted in /volume1/web/wordpress/wp-content/plugins/front-end-pm-pro/pro/fep-email-parser/mimeDecode.php on line 65
[06-Oct-2018 04:28:27 UTC] PHP Fatal error: require_once(): Failed opening required ‘PEAR.php’ (include_path=’.:/var/packages/PEAR/target’) in /volume1/web/wordpress/wp-content/plugins/front-end-pm-pro/pro/fep-email-parser/mimeDecode.php on line 65