After a long time scratching my head finally got this bug fixed. The reason is that the table prefix is not appeded in the query which is resulting table “sms_message_list_xref” not found. The fix is - to append the MAUTIC_TABLE_PREFIX in these 2 files -
Line#149 in file - app/bundles/SmsBundle/Entity/Sms.php
->setJoinTable(MAUTIC_TABLE_PREFIX.'sms_message_list_xref')
and in Line#75 in file
app/bundles/SmsBundle/Entity/SmsRepository.php
$q->from(MAUTIC_TABLE_PREFIX.'sms_message_list_xref', 'sml')
its kinda funny how the dev team never checked this.