Problem Definition:
Users who are receiving Junk Summary emails from the Sonicwall will not be able to manage Junk box from any link in a Junk Box Summary unless they have enough privilege to access them. They cannot unjunk or delete the emails except the Sonicwall administrator.
Resolution or Workaround:
To allow all the users to manage their Junk box and unjunk or delete their own emails we need to give them “Full Access” to the quarantined messages. Goto 'Anti-spam > Junk Summary' page and Choose Frequency of Summaries from the drop-down box with the dates and times to receive email notification. Set Single Click Viewing of messages to “Full access” under Miscellaneous Settings from View messages only. 
Selecting Full Access option allows the user to check junk messages and the user will be able to see the complete message. Selecting ‘View only messages’ option will not allow the user to check junk messages and the user will not be able to see the complete message.