Does not update unless Force Updates is used

This error shows up in error_log for the website, when Easy Updates Manager attempts an automatic update (at night, as in the example, where my time zone is -7 of GMT):
[08-Feb-2018 07:21:53 UTC] PHP Fatal error: Uncaught Error: Call to undefined function request_filesystem_credentials() in /home/mtiwbixc/public_html/goodforyou/wp-admin/includes/class-wp-upgrader-skin.php:93
Stack trace:
#0 /home/mtiwbixc/public_html/goodforyou/wp-admin/includes/class-automatic-upgrader-skin.php(47): WP_Upgrader_Skin->request_filesystem_credentials(false, ‘/home/mtiwbixc/…’, true)
#1 /home/mtiwbixc/public_html/goodforyou/wp-admin/includes/class-wp-automatic-updater.php(144): Automatic_Upgrader_Skin->request_filesystem_credentials(false, ‘/home/mtiwbixc/…’, true)
#2 /home/mtiwbixc/public_html/goodforyou/wp-admin/includes/update.php(85): WP_Automatic_Updater->should_update(‘core’, Object(stdClass), ‘/home/mtiwbixc/…’)
#3 /home/mtiwbixc/public_html/goodforyou/wp-includes/update.php(215): find_core_auto_update()
#4 /home/mtiwbixc/public_html/goodforyou/wp-includes/class-wp-hook.php(286): wp_version_check()
#5 /home/mtiwbixc/public_html/goodforyou/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(”, Array)
#6 /home/mtiwbixc in /home/mtiwbixc/public_html/goodforyou/wp-admin/includes/class-wp-upgrader-skin.php on line 93

As a result, no updating is done. I visit a site and have to use Force Updates, which also causes the error, but at least the updates are done this way.