Fatal Error Message in wordpress

Since the update to wordpress 5.8 and php 8.06 I get the message you see below.
PPlease help.

WordPress-Version 5.8

Aktuelles Theme: Enfold Child (Version 1.0)

Aktuelles Plugin: MailPoet 3 (New) (Version 3.65.1)

PHP-Version 8.0.6

Fehler-Details

==============

Ein Fehler vom Typ E_ERROR wurde in der Zeile 2 der Datei /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Driver/AbstractMySQLDriver.php verursacht. Fehlermeldung: Uncaught PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away in /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOConnection.php:2

Stack trace:

#0 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOConnection.php(2): PDO->query('SELECT w0_.name...', NULL)

#1 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOQueryImplementation.php(2): MailPoetVendor\Doctrine\DBAL\Driver\PDOConnection->doQuery('SELECT w0_.name...', NULL)

#2 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(2): MailPoetVendor\Doctrine\DBAL\Driver\PDOConnection->query('SELECT w0_.name...')

#3 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/Query/Exec/SingleSelectExecutor.php(2): MailPoetVendor\Doctrine\DBAL\Connection->executeQuery('SELECT w0_.name...', Array, Array, NULL)

#4 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/Query.php(2): MailPoetVendor\Doctrine\ORM\Query\Exec\SingleSelectExecutor->execute(Object(MailPoet\Doctrine\SerializableConnection), Array, Array)

#5 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/AbstractQuery.php(2): MailPoetVendor\Doctrine\ORM\Query->_doExecute()

#6 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/AbstractQuery.php(2): MailPoetVendor\Doctrine\ORM\AbstractQuery->executeIgnoreQueryCache(NULL, 1)

#7 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/AbstractQuery.php(2): MailPoetVendor\Doctrine\ORM\AbstractQuery->execute(NULL, 1)

#8 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/lib/Form/FormsRepository.php(30): MailPoetVendor\Doctrine\ORM\AbstractQuery->getResult()

#9 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/lib/PostEditorBlocks/SubscriptionFormBlock.php(47): MailPoet\Form\FormsRepository->findAllNotDeleted()

#10 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-includes/class-wp-hook.php(303): MailPoet\PostEditorBlocks\SubscriptionFormBlock->MailPoet\PostEditorBlocks\{closure}('')

#11 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters(NULL, Array)

#12 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-includes/plugin.php(470): WP_Hook->do_action(Array)

#13 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-admin/admin-header.php(147): do_action('admin_head')

#14 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-admin/admin.php(239): require_once('/www/htdocs/w00...')

#15 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-admin/tools.php(40): require_once('/www/htdocs/w00...')

#16 {main}

Next MailPoetVendor\Doctrine\DBAL\Driver\PDO\Exception: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away in /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDO/Exception.php:2

Stack trace:

#0 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOConnection.php(2): MailPoetVendor\Doctrine\DBAL\Driver\PDO\Exception::new(Object(PDOException))

#1 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOQueryImplementation.php(2): MailPoetVendor\Doctrine\DBAL\Driver\PDOConnection->doQuery('SELECT w0_.name...', NULL)

#2 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(2): MailPoetVendor\Doctrine\DBAL\Driver\PDOConnection->query('SELECT w0_.name...')

#3 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/Query/Exec/SingleSelectExecutor.php(2): MailPoetVendor\Doctrine\DBAL\Connection->executeQuery('SELECT w0_.name...', Array, Array, NULL)

#4 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/Query.php(2): MailPoetVendor\Doctrine\ORM\Query\Exec\SingleSelectExecutor->execute(Object(MailPoet\Doctrine\SerializableConnection), Array, Array)

#5 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/AbstractQuery.php(2): MailPoetVendor\Doctrine\ORM\Query->_doExecute()

#6 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/AbstractQuery.php(2): MailPoetVendor\Doctrine\ORM\AbstractQuery->executeIgnoreQueryCache(NULL, 1)

#7 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/AbstractQuery.php(2): MailPoetVendor\Doctrine\ORM\AbstractQuery->execute(NULL, 1)

#8 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/lib/Form/FormsRepository.php(30): MailPoetVendor\Doctrine\ORM\AbstractQuery->getResult()

#9 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/lib/PostEditorBlocks/SubscriptionFormBlock.php(47): MailPoet\Form\FormsRepository->findAllNotDeleted()

#10 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-includes/class-wp-hook.php(303): MailPoet\PostEditorBlocks\SubscriptionFormBlock->MailPoet\PostEditorBlocks\{closure}('')

#11 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters(NULL, Array)

#12 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-includes/plugin.php(470): WP_Hook->do_action(Array)

#13 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-admin/admin-header.php(147): do_action('admin_head')

#14 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-admin/admin.php(239): require_once('/www/htdocs/w00...')

#15 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-admin/tools.php(40): require_once('/www/htdocs/w00...')

#16 {main}

Next MailPoetVendor\Doctrine\DBAL\Exception\ConnectionLost: An exception occurred while executing 'SELECT w0_.name AS name_0, w0_.body AS body_1, w0_.status AS status_2, w0_.settings AS settings_3, w0_.styles AS styles_4, w0_.id AS id_5, w0_.created_at AS created_at_6, w0_.updated_at AS updated_at_7, w0_.deleted_at AS deleted_at_8 FROM wp_mailpoet_forms w0_ WHERE w0_.deleted_at IS NULL ORDER BY w0_.updated_at DESC':

SQLSTATE[HY000]: General error: 2006 MySQL server has gone away in /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Driver/AbstractMySQLDriver.php:2

Stack trace:

#0 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php(2): MailPoetVendor\Doctrine\DBAL\Driver\AbstractMySQLDriver->convertException('An exception oc...', Object(MailPoetVendor\Doctrine\DBAL\Driver\PDO\Exception))

#1 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/DBALException.php(2): MailPoetVendor\Doctrine\DBAL\DBALException::wrapException(Object(MailPoetVendor\Doctrine\DBAL\Driver\PDO\MySQL\Driver), Object(MailPoetVendor\Doctrine\DBAL\Driver\PDO\Exception), 'An exception oc...')

#2 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(2): MailPoetVendor\Doctrine\DBAL\DBALException::driverExceptionDuringQuery(Object(MailPoetVendor\Doctrine\DBAL\Driver\PDO\MySQL\Driver), Object(MailPoetVendor\Doctrine\DBAL\Driver\PDO\Exception), 'SELECT w0_.name...', Array)

#3 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(2): MailPoetVendor\Doctrine\DBAL\Connection->handleExceptionDuringQuery(Object(MailPoetVendor\Doctrine\DBAL\Driver\PDO\Exception), 'SELECT w0_.name...', Array, Array)

#4 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/Query/Exec/SingleSelectExecutor.php(2): MailPoetVendor\Doctrine\DBAL\Connection->executeQuery('SELECT w0_.name...', Array, Array, NULL)

#5 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/Query.php(2): MailPoetVendor\Doctrine\ORM\Query\Exec\SingleSelectExecutor->execute(Object(MailPoet\Doctrine\SerializableConnection), Array, Array)

#6 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/AbstractQuery.php(2): MailPoetVendor\Doctrine\ORM\Query->_doExecute()

#7 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/AbstractQuery.php(2): MailPoetVendor\Doctrine\ORM\AbstractQuery->executeIgnoreQueryCache(NULL, 1)

#8 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/AbstractQuery.php(2): MailPoetVendor\Doctrine\ORM\AbstractQuery->execute(NULL, 1)

#9 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/lib/Form/FormsRepository.php(30): MailPoetVendor\Doctrine\ORM\AbstractQuery->getResult()

#10 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-content/plugins/mailpoet/lib/PostEditorBlocks/SubscriptionFormBlock.php(47): MailPoet\Form\FormsRepository->findAllNotDeleted()

#11 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-includes/class-wp-hook.php(303): MailPoet\PostEditorBlocks\SubscriptionFormBlock->MailPoet\PostEditorBlocks\{closure}('')

#12 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-includes/class-wp-hook.php(327): WP_Hook->apply_filters(NULL, Array)

#13 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-includes/plugin.php(470): WP_Hook->do_action(Array)

#14 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-admin/admin-header.php(147): do_action('admin_head')

#15 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-admin/admin.php(239): require_once('/www/htdocs/w00...')

#16 /www/htdocs/w00b6cdc/webseite-relaunch-2017/wp-admin/tools.php(40): require_once('/www/htdocs/w00...')

#17 {main}

  thrown