errors

Hi,

Suddenly the plugin isn’t working anymore.
I get the following errors in my logs:

2020-11-12T10:25:35+00:00 CRITICAL Uncaught Error: [] operator not supported for strings in /home/flo/domains/doyouknowflo.nl/public_html/wp-content/plugins/woocommerce-advanced-shipping/includes/class-was-method.php:82
Stack trace:
#0 /home/flo/domains/doyouknowflo.nl/public_html/wp-content/plugins/woocommerce-advanced-shipping/includes/class-was-method.php(23): Was_Advanced_Shipping_Method->was_match_methods()
#1 /home/flo/domains/doyouknowflo.nl/public_html/wp-content/plugins/woocommerce/includes/class-wc-shipping.php(199): Was_Advanced_Shipping_Method->__construct()
#2 /home/flo/domains/doyouknowflo.nl/public_html/wp-content/plugins/woocommerce/includes/class-wc-shipping.php(177): WC_Shipping->register_shipping_method('Was_Advanced_Sh...')
#3 /home/flo/domains/doyouknowflo.nl/public_html/wp-content/plugins/woocommerce/includes/class-wc-shipping.php(221): WC_Shipping->load_shipping_methods()
#4 /home/flo/domains/doyouknowflo.nl/public_html/wp-content/plugins/woocommerce/includes/wc-core-functions.php(1663): WC_Shipping->get_shipping_methods in /home/flo/domains/doyouknowflo.nl/public_html/wp-content/plugins/woocommerce-advanced-shipping/includes/class-was-method.php op de lijn 82

Can you please help me?
Regards, Bas