Hello,
we had technician last night at the router place that had no WAN access to the router and he met with the situation:
> WAN access was turned off - it was 100% sure that was turned on during the configuration
> we cannot control via SMS because there was 7 stored sms.
After removing these SMS there came another 3, after removing them there came another package of SMS.
After cleaning SMS storage from all SMS we could control via SMS Management.
Router is working with firmware 6.06.1 and did not even required reboot.