Reply All issues... Mail App

Hi All,

I’ve just installed NextCloud Version 21.0.3. I’ve only enabled the Mail and Contacts app. Sending email through the next cloud app is working fine if I go about “+ New message”. When I type the user name in the To field it appears that the Mail app references my contacts and provides a completion.

I have noticed though when someone sends me an email which has a number of CC’d users that I “reply All” to I get an Error 500 issue. The odd thing is that I can send email to everyone on the list… When I reference the NextCloud logs I found:

OCA\Mail\Exception\ServiceException: Could not send message: Error when communicating with the server.
/home/nextcloud/apps/mail/lib/Controller/AccountsController.php - line 433:

OCA\Mail\Service\MailTransmission->sendMessage()

/home/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 218:

OCA\Mail\Controller\AccountsController->send()

/home/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 127:

OC\AppFramework\Http\Dispatcher->executeController()

/home/nextcloud/lib/private/AppFramework/App.php - line 157:

OC\AppFramework\Http\Dispatcher->dispatch()

/home/nextcloud/lib/private/Route/Router.php - line 302:

OC\AppFramework\App::main()

/home/nextcloud/lib/base.php - line 993:

OC\Route\Router->match()

/home/nextcloud/index.php - line 37:

OC::handleRequest()

Caused by Horde_Mime_Exception: Error when communicating with the server.
/home/nextcloud/apps/mail/vendor/pear-pear.horde.org/Horde_Mime/Horde/Mime/Mail.php - line 479:

Horde_Mime_Part->send()

/home/nextcloud/apps/mail/lib/Service/MailTransmission.php - line 193:

Horde_Mime_Mail->send()

/home/nextcloud/apps/mail/lib/Controller/AccountsController.php - line 433:

OCA\Mail\Service\MailTransmission->sendMessage()

/home/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 218:

OCA\Mail\Controller\AccountsController->send()

/home/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 127:

OC\AppFramework\Http\Dispatcher->executeController()

/home/nextcloud/lib/private/AppFramework/App.php - line 157:

OC\AppFramework\Http\Dispatcher->dispatch()

/home/nextcloud/lib/private/Route/Router.php - line 302:

OC\AppFramework\App::main()

/home/nextcloud/lib/base.php - line 993:

OC\Route\Router->match()

/home/nextcloud/index.php - line 37:

OC::handleRequest()

Caused by Horde_Mail_Exception: Error when communicating with the server.
/home/nextcloud/apps/mail/vendor/pear-pear.horde.org/Horde_Mime/Horde/Mime/Part.php - line 1620:

Horde_Mail_Transport_Smtphorde->send()

/home/nextcloud/apps/mail/vendor/pear-pear.horde.org/Horde_Mime/Horde/Mime/Mail.php - line 479:

Horde_Mime_Part->send()

/home/nextcloud/apps/mail/lib/Service/MailTransmission.php - line 193:

Horde_Mime_Mail->send()

/home/nextcloud/apps/mail/lib/Controller/AccountsController.php - line 433:

OCA\Mail\Service\MailTransmission->sendMessage()

/home/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 218:

OCA\Mail\Controller\AccountsController->send()

/home/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 127:

OC\AppFramework\Http\Dispatcher->executeController()

/home/nextcloud/lib/private/AppFramework/App.php - line 157:

OC\AppFramework\Http\Dispatcher->dispatch()

/home/nextcloud/lib/private/Route/Router.php - line 302:

OC\AppFramework\App::main()

/home/nextcloud/lib/base.php - line 993:

OC\Route\Router->match()

/home/nextcloud/index.php - line 37:

OC::handleRequest()

Caused by Horde_Smtp_Exception: Error when communicating with the server.
/home/nextcloud/apps/mail/vendor/pear-pear.horde.org/Horde_Smtp/Horde/Smtp.php - line 1028:

Horde_Smtp_Connection->read()

/home/nextcloud/apps/mail/vendor/pear-pear.horde.org/Horde_Smtp/Horde/Smtp.php - line 641:

Horde_Smtp->_getResponse()

/home/nextcloud/apps/mail/vendor/pear-pear.horde.org/Horde_Mail/Horde/Mail/Transport/Smtphorde.php - line 143:

Horde_Smtp->send()

/home/nextcloud/apps/mail/vendor/pear-pear.horde.org/Horde_Mime/Horde/Mime/Part.php - line 1620:

Horde_Mail_Transport_Smtphorde->send()

/home/nextcloud/apps/mail/vendor/pear-pear.horde.org/Horde_Mime/Horde/Mime/Mail.php - line 479:

Horde_Mime_Part->send()

/home/nextcloud/apps/mail/lib/Service/MailTransmission.php - line 193:

Horde_Mime_Mail->send()

/home/nextcloud/apps/mail/lib/Controller/AccountsController.php - line 433:

OCA\Mail\Service\MailTransmission->sendMessage()

/home/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 218:

OCA\Mail\Controller\AccountsController->send()

/home/nextcloud/lib/private/AppFramework/Http/Dispatcher.php - line 127:

OC\AppFramework\Http\Dispatcher->executeController()

/home/nextcloud/lib/private/AppFramework/App.php - line 157:

OC\AppFramework\Http\Dispatcher->dispatch()

/home/nextcloud/lib/private/Route/Router.php - line 302:

OC\AppFramework\App::main()

/home/nextcloud/lib/base.php - line 993:

OC\Route\Router->match()

/home/nextcloud/index.php - line 37:

OC::handleRequest()

Any advice?