E_ERROR was caused in line 205 Portokasse.php

Hallo,

wenn ich mich über die Portokasse mit den korrekten Zugangsdaten einlogge erhalte ich folgende Fehlermeldung.

Wie l?sst sich das beheben ? Vielen Dank.

Error Details
=============
An error of type E_ERROR was caused in line 205 of the file /var/www/vhosts/beeskin.com/httpdocs/wp-content/plugins/woo-dp-internetmarke/includes/Settings/Portokasse.php. Error message: Uncaught Error: Call to a member function get() on bool in /var/www/vhosts/beeskin.com/httpdocs/wp-content/plugins/woo-dp-internetmarke/includes/Settings/Portokasse.php:205
Stack trace:
#0 /var/www/vhosts/beeskin.com/httpdocs/wp-includes/class-wp-hook.php(294): DeutschePost\Internetmarke\Settings\Portokasse->sanitizeSettings()
#1 /var/www/vhosts/beeskin.com/httpdocs/wp-includes/plugin.php(212): WP_Hook->apply_filters()
#2 /var/www/vhosts/beeskin.com/httpdocs/wp-includes/formatting.php(4907): apply_filters()
#3 /var/www/vhosts/beeskin.com/httpdocs/wp-includes/option.php(369): sanitize_option()
#4 /var/www/vhosts/beeskin.com/httpdocs/wp-admin/options.php(314): update_option()
#5 {main}
thrown`