Contact form error

I have a contact form template from Nimble Builder on my homepage. Everything worked a couple days ago. But when I try to send a message now, I get an error with this message:

Notice: Undefined index: email_field_label in /home/e91groep3/domains/allaboutsushi.nl/public_html/wp-content/plugins/nimble-builder/inc/sektions/ccat-sektions.php on line 12127

Fatal error: Uncaught Error: Call to a member function get_input() on null in /home/e91groep3/domains/allaboutsushi.nl/public_html/wp-content/plugins/nimble-builder/inc/sektions/ccat-sektions.php:12717 Stack trace: #0 /home/e91groep3/domains/allaboutsushi.nl/public_html/wp-content/plugins/nimble-builder/inc/sektions/ccat-sektions.php(11981): Nimble\Sek_Mailer->maybe_send(Array, Array) #1 /home/e91groep3/domains/allaboutsushi.nl/public_html/wp-includes/class-wp-hook.php(286): Nimble\Sek_Simple_Form->simple_form_parse_request(Object(WP)) #2 /home/e91groep3/domains/allaboutsushi.nl/public_html/wp-includes/class-wp-hook.php(310): WP_Hook->apply_filters(NULL, Array) #3 /home/e91groep3/domains/allaboutsushi.nl/public_html/wp-includes/plugin.php(531): WP_Hook->do_action(Array) #4 /home/e91groep3/domains/allaboutsushi.nl/public_html/wp-includes/class-wp.php(387): do_action_ref_array(‘parse_request’, Array) #5 /home/e91groep3/domains/allaboutsushi.nl/public_html/wp-includes/class-wp.php(737): WP->parse_request(”) #6 /home/e91groe in /home/e91groep3/domains/allaboutsushi.nl/public_html/wp-content/plugins/nimble-builder/inc/sektions/ccat-sektions.php on line 12717

How do I fix this? I’ve tried to delete it and place it again, but that did not help.

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