[Gelöst] I have problem

Background of the issue:
I have been seeing some problems with the site lately. In the WPML+ACF Pro bundle, my fields in the translation groups periodically disappear. Now there is a duplication of fields of different languages on the translated page. I installed Query Monitor on the site and I see that there are problems with WPML. Notice unserialize(): Error at offset 150 of 223 bytes wp-includes/functions.php:650 unserialize() wp-includes/functions.php:650 maybe_unserialize() wp-includes/option.php:247 get_option() wp-content/plugins/sitepress-multilingual-cms/classes/ATE/API/ClonedSites/Lock.php:67 WPMLTACLock::isLocked() wp-content/plugins/sitepress-multilingual-cms/classes/menu/mcsetup/class-wpml-tm-mcs-ate.php:57 WPML_TM_MCS_ATE->__construct() wp-content/plugins/sitepress-multilingual-cms/classes/menu/class-wpml-tm-scripts-factory.php:249 WPML_TM_Scripts_Factory->create_ate() wp-content/plugins/sitepress-multilingual-cms/classes/menu/class-wpml-tm-scripts-factory.php:215 WPML_TM_Scripts_Factory->build_localize_script_data() wp-content/plugins/sitepress-multilingual-cms/classes/menu/class-wpml-tm-scripts-factory.php:206 WPML_TM_Scripts_Factory->localize_script() wp-content/plugins/sitepress-multilingual-cms/classes/menu/class-wpml-tm-scripts-factory.php:206 WPMLFI_Invoker->__invoke() wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/Either.php:207 WPMLFPRight->map() wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/Either.php:257 WPMLFPRight->chain() wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/Promise.php:24 WPMLFPPromise->resolve() wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/Promise.php:30 WPMLFPPromise->resolve() wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/Promise.php:30 WPMLFPPromise->resolve() wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/Promise.php:30 WPMLFPPromise->resolve() wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/Promise.php:30 WPMLFPPromise->resolve() wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/fp/core/Promise.php:30 WPMLFPPromise->resolve() wp-content/plugins/sitepress-multilingual-cms/vendor/wpml/wp/classes/Hooks.php:50 WPMLLWHooks::WPMLLW{closure}() wp-includes/class-wp-hook.php:324 do_action('wp_loaded') wp-settings.php:722 another problems what i see just at WPML plugin page is: Warning session_start(): open(/var/lib/php/session/sess_d1f1t66q5v7j7as01d1jprsksp, O_RDWR) failed: Permission denied (13) wp-content/plugins/sitepress-multilingual-cms/inc/translation-management/translation-management.class.php:115 session_start() wp-content/plugins/sitepress-multilingual-cms/inc/translation-management/translation-management.class.php:115 TranslationManagement->__construct() wp-content/plugins/sitepress-multilingual-cms/inc/functions-load.php:286 wpml_load_core_tm() wp-content/plugins/sitepress-multilingual-cms/sitepress.class.php:1695 SitePress->get_custom_fields_translation_settings() wp-content/plugins/sitepress-multilingual-cms/classes/API/Hooks/class-wpml-api-hooks-factory.php:13 WPML_API_Hooks_Factory->create() wp-content/plugins/sitepress-multilingual-cms/classes/action-filter-loader/class-wpml-action-filter-loader.php:148 WPML_Action_Filter_Loader->run_factory() wp-content/plugins/sitepress-multilingual-cms/classes/action-filter-loader/class-wpml-action-filter-loader.php:96 WPML_Action_Filter_Loader->load_factory() wp-content/plugins/sitepress-multilingual-cms/classes/action-filter-loader/class-wpml-action-filter-loader.php:80 WPML_Action_Filter_Loader->load_factory_or_action() wp-content/plugins/sitepress-multilingual-cms/classes/action-filter-loader/class-wpml-action-filter-loader.php:49 WPML_Action_Filter_Loader->load() wp-content/plugins/sitepress-multilingual-cms/sitepress.php:267 1 Plugin: sitepress-multilingual-cms and Warning session_start(): Failed to read session data: files (path: /var/lib/php/session) wp-content/plugins/sitepress-multilingual-cms/inc/translation-management/translation-management.class.php:115 session_start() wp-content/plugins/sitepress-multilingual-cms/inc/translation-management/translation-management.class.php:115 TranslationManagement->__construct() wp-content/plugins/sitepress-multilingual-cms/inc/functions-load.php:286 wpml_load_core_tm() wp-content/plugins/sitepress-multilingual-cms/sitepress.class.php:1695 SitePress->get_custom_fields_translation_settings() wp-content/plugins/sitepress-multilingual-cms/classes/API/Hooks/class-wpml-api-hooks-factory.php:13 WPML_API_Hooks_Factory->create() wp-content/plugins/sitepress-multilingual-cms/classes/action-filter-loader/class-wpml-action-filter-loader.php:148 WPML_Action_Filter_Loader->run_factory() wp-content/plugins/sitepress-multilingual-cms/classes/action-filter-loader/class-wpml-action-filter-loader.php:96 WPML_Action_Filter_Loader->load_factory() wp-content/plugins/sitepress-multilingual-cms/classes/action-filter-loader/class-wpml-action-filter-loader.php:80 WPML_Action_Filter_Loader->load_factory_or_action() wp-content/plugins/sitepress-multilingual-cms/classes/action-filter-loader/class-wpml-action-filter-loader.php:49 WPML_Action_Filter_Loader->load() wp-content/plugins/sitepress-multilingual-cms/sitepress.php:267

Symptoms:
Fields in the translation groups periodically disappear, duplication of fields of different languages on the translated page, unserialize() error, session_start() permission denied, and failed to read session data.

Questions:
How to fix thats problems?