Missing permission prevents user to approve branch by email

People approving branch through email are getting the following OOPSes

OOPS-1552CEMAIL139
OOPS-1552CEMAIL150
OOPS-1563CEMAIL261
OOPS-1572CEMAIL173
OOPS-1572CEMAIL224
OOPS-1573CEMAIL129
OOPS-1573CEMAIL130

The traceback is:

  ProgrammingError: permission denied for relation codeimport

    Traceback (most recent call last):
  Module canonical.launchpad.mail.incoming, line 297, in handleMail
    handled = handler.process(mail, email_addr, file_alias)
  Module lp.code.mail.codehandler, line 258, in process
    return self.processComment(mail, email_addr, file_alias)
  Module lp.code.mail.codehandler, line 326, in processComment
    processed_count = self.processCommands(context, email_body_text)
  Module lp.code.mail.codehandler, line 291, in processCommands
    command.execute(context)
  Module lp.code.mail.codehandler, line 175, in execute
    context.merge_proposal.approveBranch(context.user, rev_id)
  Module canonical.database.sqlbase, line 728, in block_implicit_flushes_decorator
    return func(*args, **kwargs)
  Module canonical.launchpad.webapp.authorization, line 203, in checkPermission
    principal.account)
  Module canonical.launchpad.security, line 168, in checkAccountAuthenticated
    return self.checkAuthenticated(IPersonRoles(person))
  Module canonical.launchpad.security, line 1878, in checkAuthenticated
    check_permission('launchpad.Edit', self.obj.target_branch) or
  Module canonical.launchpad.webapp.authorization, line 236, in check_permission
    return zcheckPermission(permission_name, context)
  Module zope.security.management, line 143, in checkPermission
  Module canonical.database.sqlbase, line 728, in block_implicit_flushes_decorator
    return func(*args, **kwargs)
  Module canonical.launchpad.webapp.authorization, line 203, in checkPermission
    principal.account)
  Module canonical.launchpad.security, line 168, in checkAccountAuthenticated
    return self.checkAuthenticated(IPersonRoles(person))
  Module canonical.launchpad.security, line 1675, in checkAuthenticated
    code_import = self.obj.code_import
  Module lp.code.model.branch, line 575, in code_import
    return CodeImportSet().getByBranch(self)
  Module lp.code.model.codeimport, line 322, in getByBranch
    return CodeImport.selectOneBy(branch=branch)
  Module storm.sqlobject, line 356, in selectOneBy
  Module storm.sqlobject, line 516, in _one
  Module storm.store, line 1114, in one
  Module storm.databases.postgres, line 249, in execute
  Module storm.database, line 217, in execute
  Module storm.databases.postgres, line 259, in raw_execute
  Module storm.database, line 299, in raw_execute
  Module storm.database, line 342, in _check_disconnect
ProgrammingError: permission denied for relation codeimport