I got a '451 4.3.5 Requested action aborted: local error processing' error

This error occurs when Icewarp Email Server is trying to read or write to a disk and fails.

SYSTEM [00007F1EF4E05700] 12:00:00 MDA *** <tonny@icewarp.com> <user@icewarp.onice.io> 1 4227 00:00:00 ERROR 202006131200000001
SYSTEM [00007F1EF4E05700] 12:00:00 MDA 451 4.3.5 Requested action aborted: local error processing

The most probable causes of this problem are listed below:

1. The directories set in the System -> Storage -> Directories tab do not exist
2. The Icewarp Service does not have the correct access permissions to the above directories
3. A disk drive is full
4. User's inbox does not exist
5. Your disk is somehow corrupted
6. A user is very close to exceeding the mailbox size limit and he/she tries to send a message via WebMail and save such message to the Sent folder
7. AntiSpam live is rejecting the outgoing message. Set the following options to "Add spam score" instead of "Reject". Console > AntiSpam > AntiSpam Live > Outgoing AntiSpam > "Outgoing bulk and suspicious spam message action" and "Outgoing confirmed spam message action".