I'm facing a pretty funny situation in spite of validating all the settings against the documented one.
I had one queue till now for which an email account had been set up & associated with it. The queue used this account to send mails & to receive mails into the queues i.e. it creates an automatic ticket upon sending a mail to this mail ID. Also, some auto-responses had been configured & associated with the same queue & were sending mails in an appropriate manner.
Note: This mail account is the Standard address(default address) I'm using for it.
Now, the issue is when I create a new queue and associate different mail account & different set of auto-responses to it.
I tried replicating settings used in the former for the latter one, but I'm not finding any success in this.
I have created a valid mail account & associated it to the new queue by following these steps:
Email settings -> Email addresses -> Add System Address
Email address = "test@test.com"
Display name = "test"
Queue = "test2" (This is the new queue which had been earlier associated to the new mail account(test@test.com) while creating it)
Valid = "valid"
Email Settings - > Postmaster Mail Accounts -> Add Mail Account
Type = "POP3S"
Username/Password/Host = "test/test/mail.test.com"
Trusted = "yes"
Dispatching = "Dispatching by selected queue"
Queue = "test2"
valid = "valid"
I have created some new auto-responses & associated them with this new mail account.
Also, the queue has been associated to the auto-responses through Queues->Auto-Responses.
Now, when I go & create a ticket in the queue "test2", the application breaks & returns a blank page. Note that the ticket indeed is created & logged as well in the ticket description(The decription also tells that the mail has been sent from the new mail account but it isn't so. I didn't receive any mail either). Whereas when I associate this new queue to the earlier set of auto-responses(the one which is working fine), it works fine & shoots out mails appropriately.
Please help me out if I'm missing anything. This needs to be rectified on high priority.
Note: I've checked the mail accounts. They're working & correct credentials have been updated in OTRS.
Thanks.

System Email Address Management -> Queue*".