E_ERROR was caused in line 108 Uncaught PDOException

I’ve had this error emailed to me twice in the last couple of weeks by my WordPress, the second time being today.

What the hey is it all about and how the frack do I fix it?

Many thanks in advance.

When seeking help with this issue, you may be asked for some of the following information:
WordPress version 5.3.2
Current theme: GeneratePress (version 2.4.1)
Current plugin: MailPoet 3 (New) (version 3.46.0)
PHP version 7.3.13

Error Details
=============
An error of type E_ERROR was caused in line 108 of the file /home/**mysite**/public_html/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Driver/AbstractMySQLDriver.php. Error message: Uncaught PDOException: SQLSTATE[HY000]: General error: 2006 MySQL server has gone away in /home/**mysite**/public_html/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOConnection.php:98
Stack trace:
#0 /home/**mysite**/public_html/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Driver/PDOConnection.php(98): PDO->query(‘SELECT t0.name …’)
#1 /home/**mysite**/public_html/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/dbal/lib/Doctrine/DBAL/Connection.php(736): MailPoetVendor\Doctrine\DBAL\Driver\PDOConnection->query(‘SELECT t0.name …’)
#2 /home/**mysite**/public_html/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/Persisters/Entity/BasicEntityPersister.php(699): MailPoetVendor\Doctrine\DBAL\Connection->executeQuery(‘SELECT t0.name …’, Array, Array)
#3 /home/**mysite**/public_html/wp-content/plugins/mailpoet/vendor-prefixed/doctrine/orm/lib/Doctrine/ORM/EntityRepository.php(167): MailPoetVendor\Doctri

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