Activation of MPOS and CPOS, data is not syncing with DB Dynamics 365

Dear all,

I had done all the configuration at back office and had check all the prerequisites which i mentioned below, but data is not syncing with DB, in download session its showing available status.

1. We set  “IsAnonymousEnabled" value="true"
2. Batch server assign with Batch group.
3. We verify the retail server health check passes both the db connection and RTS.
4. We click Initialize button  to generate new retail seed data.
5. We Initialize Retail Scheduler job with delete existing configuration" set to "yes". 
6. We restart the "Microsoft Dynamics AX Batch Service" on all AOS VMs.
7. Then run the 9999 job from channel database.
8. We also check the URL.

Note: I have few question regards to channel database.

1. What is Data Writing batch job and why we use this job and what it is does?
2. Suppose we will create a new channel database, we have found that at that time Data writing batch job field is non-editable, how we can attached the batch job on it?, with the help of table?, And does is it relevant to dynamics 365 or for old version?