Error after migration

Hello,
We have migrated our WordPress environment to a different server and have encountered the following error.
Can you please tell us how to solve this problem, because we like EasyWatermark very much and would like to continue using it.

Fatal error: Uncaught TypeError: call_user_func_array(): Argument #1 ($callback) must be a valid callback, 
first array member is not a valid class name or object in /home/xxx/abc/DocumentRoot/wp-includes/class-wp-hook.php:292
Stack trace: #0 /home/xxx/abc/DocumentRoot/wp-includes/class-wp-hook.php(316): WP_Hook->apply_filters('', Array) #1 /home/xxx/abc/DocumentRoot/wp-includes/plugin.php(484):
WP_Hook->do_action(Array) #2 /home/xxx/abc/DocumentRoot/wp-content/plugins/easy-watermark/src/classes/Settings/Section.php(55):
do_action('easy-watermark/...', Object(EasyWatermark\Settings\Section)) #3 /home/xxx/abc/DocumentRoot/wp-content/plugins/easy-watermark/src/classes/Backup/Manager.php(69):
EasyWatermark\Settings\Section->__construct('Backup', 'backup') #4 /home/xxx/abc/DocumentRoot/wp-includes/class-wp-hook.php(292):
EasyWatermark\Backup\Manager->register_settings_section(Object(EasyWatermark\Settings\Settings)) #5 /home/xxx/abc/DocumentRoot/wp-includes/class-wp-hook.php(316):
WP_Hook->apply_filters('', Array) #6 /home/xxx/abc/DocumentRoot/wp-includes/plugin.php(484):
WP_Hook->do_action(Array) #7 /home/xxx/abc/DocumentRoot/wp-content/plugins/easy-watermark/src/classes/Settings/Settings.php(60):
do_action('easy-watermark/...', Object(EasyWatermark\Settings\Settings)) #8 /home/xxx/abc/DocumentRoot/wp-content/plugins/easy-watermark/src/classes/Settings/Settings.php(49):
EasyWatermark\Settings\Settings->register_sections() #9 /home/xxx/abc/DocumentRoot/wp-content/plugins/easy-watermark/vendor/micropackage/singleton/src/Singleton.php(58):
EasyWatermark\Settings\Settings->__construct() #10 /home/xxx/abc/DocumentRoot/wp-content/plugins/easy-watermark/src/classes/Watermark/Handler.php(75):
Micropackage\Singleton\Singleton::get() #11 /home/xxx/abc/DocumentRoot/wp-content/plugins/easy-watermark/src/classes/Core/Plugin.php(217):
EasyWatermark\Watermark\Handler->__construct() #12 /home/xxx/abc/DocumentRoot/wp-content/plugins/easy-watermark/src/classes/Features/WatermarkPreview.php(67):
EasyWatermark\Core\Plugin->get_watermark_handler() #13 /home/xxx/abc/DocumentRoot/wp-content/plugins/easy-watermark/src/classes/Core/Plugin.php(102):
EasyWatermark\Features\WatermarkPreview->__construct(Object(EasyWatermark\Core\Plugin)) #14 /home/xxx/abc/DocumentRoot/wp-includes/class-wp-hook.php(290):
EasyWatermark\Core\Plugin->setup() #15 /home/xxx/abc/DocumentRoot/wp-includes/class-wp-hook.php(316):
WP_Hook->apply_filters(Object(ezTOC), Array) #16 /home/xxx/abc/DocumentRoot/wp-includes/plugin.php(484):
WP_Hook->do_action(Array) #17 /home/xxx/abc/DocumentRoot/wp-settings.php(423):
do_action('plugins_loaded') #18 /home/xxx/abc/wp-config.php(88):
require_once('/home/kusanagi/...') #19 /home/xxx/abc/DocumentRoot/wp-load.php(42):
require_once('/home/kusanagi/...') #20 /home/xxx/abc/DocumentRoot/wp-login.php(12):
require('/home/kusanagi/...') #21 {main} thrown in /home/xxx/abc/DocumentRoot/wp-includes/class-wp-hook.php on line 292

Environment:
EasyWatermark 1.0.11
WordPress 5.7.2
PHP 8.0

Migration was performed manually.
Files: download and upload
DB: dump and restore

To isolate the problem, we tried the following
Disable EasyWatermark: WordPress started successfully.
Uninstall EasyWatermark, install the latest version again, and activate it: WordPress failed to start (same error)
Restart server: WordPress failed to start (same error)

Supplemental:
It is possible that the same phenomenon occurred in the old environment because the server was not restarted for a long period of time in the old environment.
Unfortunately, we cannot test this in the old environment.

Points of concern:
Most of the errors seem to be related to “EasyWatermark”, but the following sentence seems to be an error about “Easy Table of Contents”.
Is it possible that this is a plugin conflict issue?

WP_Hook->apply_filters(Object(ezTOC), Array) #16 /home/xxx/abc/DocumentRoot/wp-includes/plugin.php(484):