when checked with vendor they told its working fine in genieacs…One note is acs server we are using works with all other devices properly…only these two vendors are not saving configuration after reboot.
If i change wan settings through tr069…after reboot every parameter goes to default in all sections like ssid,tr069 settings
Help me in solving this issue…
Not able to find what is going exactly wrong
Is it beacause of STUN server…I doubt?
Maybe your provisions are resetting the config on every reboot? You CAN program provisions like that. 
You can also add provisions that “react” to different events, like Periodic, Inform or Value Change (through Presets, of course).
Regarding storing configuration on CPE - contact vendor for provisioning documentation.
Although, one of core functions of TR-069 is that configuration is handled by ACS, not by CPE itself.
But, option to save “current” config in case ACS becomes unavailable (god forbit, but it COULD happen) is a good option to have. In case vendor already has this option in firmware to have a “fallback” to “last-known-config” in case ACS is unavailable at time of reboot.
so what is the solution for this? i should load config again after reboot ?
In provisioning document if it is resetting after reboot?what should i change
Well, configuration of a CPE via ACS (TR-069) is done via “provisions” - this is a script which configures a CPE - depending on type, model, serial number, etc.
You can also call “external data sources” inside provision scripts (so called ext-scripts) to check how to configure a specific CPE. See Extensions (Extensions — GenieACS Documentation 1.2.9 documentation).
Via presets, define at what events this configuration should be applied (checked) - only on BOOT (or REBOOT), after FACTORY RESET, periodically, … or on ANY event when CPE checks in with ACS to ask for “what do you have for me?”.
To see what is happening with specific CPE, you can enable debug per specific CPE under Admin/Config:
id is a device id of CPE in ACS.
In above condition, I am “monitoring” two CPEs, all communication is dumped into debug file defined in genieacs.env file:
GENIEACS_DEBUG_FILE=/var/log/genieacs/device-debug.log
Also, check CWMP access log file, also defined in genieacs.env file, to see how provisioning of CPE is progressing. Any log statements used in provisions will be logged here.
Those two logs should provide sufficient information what is going on with your CPEs at boot time, AFTER they start communcatiing with your ACS.