When swift mailer is disabled and the mailbox is enabled so in the same mailbox fetch ticket, reply in the same ticket from the admin side show an error

[komal-sh-27]

Description
When swift mailer is disabled and the mailbox is enabled so in the same mailbox fetch ticket, reply in the same ticket from the admin side show an error

How to reproduce
Step 1: Firstly setup with swift mailer and mailbox

Step 2: Now fetch tickets from this mailbox

Step 3: Now again the same swift mailer is disabled and the mailbox is enabled:

Swiftmailer is disabled:

Mailbox is enabled:

Email setting with the 2nd email for checking outgoing email notifications:

Step 4: Open the fetching ticket from the same mailbox:

and after the reply from the admin side shows an error:

Note:

If the reply from the customer side in the same ticket nothing shows an error this error is only on the admin side.

Possible Solution
If we are swift mailer is disabled and the mailbox is enabled so if the same mail fetch reply in the same ticket from the admin side should not be showing an error