Can’t activate MailPoet 3 – fatal error

Hi,

I’m trying to activate MailPoet 3 (never did before, fresh installation), but I always got a fatal error and the plugin isn’t activated.

My SetUp:
Wp Version 5.6

Server:
Server-Architektur Linux 5.4.0-62-generic x86_64
Webserver Apache
PHP-Version 7.4.10 (Unterstützt 64bit-Werte)
PHP-SAPI fpm-fcgi
Maximale PHP-Eingabe-Variablen (max_input_vars) 3000
Maximale PHP-Ausführungszeit (max_execution_time) 30
PHP-Speicher-Limit (memory_limit) 256M
Maximale Eingabe-Zeit (max_input_time) 60
Maximale Dateigr??e beim Upload (upload_max_filesize) 200M
Maximale Gr??e der PHP-Post-Daten (post_max_size) 200M
cURL-Version 7.68.0 OpenSSL/1.1.1f
Ist SUHOSIN installiert? Nein
Ist die Imagick-Bibliothek verfügbar? Ja
Werden sprechende Permalinks unterstützt? Ja
.htaccess-Regeln Individuelle Regeln wurden deiner .htaccess-Datei hinzugefügt.

Database:
Erweiterung mysqli
Server-Version 10.5.6-MariaDB-1:10.5.6+maria~focal-log
Client-Version mysqlnd 7.4.10

Error Message

Fatal error: Uncaught Error: Class ‘MailPoet\Tracy\DoctrinePanel\DoctrinePanel’ not found in /www/htdocs/w01b79d5/weinberg-schloesschen.com/wp-content/plugins/mailpoet/lib/Doctrine/EntityManagerFactory.php:53 Stack trace: #0 /www/htdocs/w01b79d5/weinberg-schloesschen.com/wp-content/plugins/mailpoet/generated/FreeCachedContainer.php(360): MailPoet\Doctrine\EntityManagerFactory->createEntityManager() #1 /www/htdocs/w01b79d5/weinberg-schloesschen.com/wp-content/plugins/mailpoet/generated/FreeCachedContainer.php(2014): MailPoetGenerated\FreeCachedContainer->getEntityManagerService() #2 /www/htdocs/w01b79d5/weinberg-schloesschen.com/wp-content/plugins/mailpoet/generated/FreeCachedContainer.php(2004): MailPoetGenerated\FreeCachedContainer->getSettingsRepositoryService() #3 /www/htdocs/w01b79d5/weinberg-schloesschen.com/wp-content/plugins/mailpoet/generated/FreeCachedContainer.php(914): MailPoetGenerated\FreeCachedContainer->getSettingsControllerService() #4 /www/htdocs/w01b79d5/weinberg-schloesschen.com/wp-content/plugins/mailp in /www/htdocs/w01b79d5/weinberg-schloesschen.com/wp-content/plugins/mailpoet/lib/Doctrine/EntityManagerFactory.php on line 53

What I tried:

deactivated all other plugins -> activated mailpoet -> activating other plugins -> fatal error

We want to switch from cleverreach to mailpoet, but I can’t get it work… ??

Any help?

Thanks
Achim

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