Error

Hello, I use this plugin for 2 years and I like it very much, but since I upgraded WordPress to version 6, it doesn’t work. I use text watermark, but it dissapeared from all my pictures. On my mailbox I’ve got message about this problem with some details:

Błąd typu E_ERROR został spowodowany w linii 622 pliku /home/gpavaiwp/www/wordpress2/wp-content/plugins/easy-watermark/src/classes/AttachmentProcessor/AttachmentProcessorGD.php. Komunikat błędu: Uncaught Error: Call to undefined function EasyWatermark\AttachmentProcessor\imagettfbbox() in /home/gpavaiwp/www/wordpress2/wp-content/plugins/easy-watermark/src/classes/AttachmentProcessor/AttachmentProcessorGD.php:622
Stack trace:
#0 /home/gpavaiwp/www/wordpress2/wp-content/plugins/easy-watermark/src/classes/AttachmentProcessor/AttachmentProcessorGD.php(508): EasyWatermark\AttachmentProcessor\AttachmentProcessorGD->calculate_text_size('20', '90', '/home/gpavaiwp/...', 'plockibus.pl   ...')
#1 /home/gpavaiwp/www/wordpress2/wp-content/plugins/easy-watermark/src/classes/AttachmentProcessor/AttachmentProcessorGD.php(358): EasyWatermark\AttachmentProcessor\AttachmentProcessorGD->apply_text_watermark(Object(EasyWatermark\Watermark\Watermark))
#2 /home/gpavaiwp/www/wordpress2/wp-content/plugins/easy-watermark/src/classes/AttachmentProcessor/AttachmentProcessorGD.php(141): EasyWatermark\AttachmentProcessor\AttachmentProcessorGD->apply_watermark(Object(EasyWatermark\Watermark\Watermark))
#3 /home/gpavaiwp/www/wordp

Is it problem with this plugin not working on WordPress 6 or something else?

The page I need help with: [log in to see the link]