This error appears due to app Re-install in phone,for resolving that error please follow the bellow steps:-

1. Go to Masters > eBusiness Setup > E business setup window will be appear > Click on Salesman setup > Salesman setup window will be appear >Select salesman & click on Modify > Change Registration id with the Marg Id(Confirm through the salesman)

2. Go to Masters > eBusiness Setup > E business setup window will be appear > Click on Validate & check cloud data > Check here how many data uploaded on server.

3. Go to Masters > eBusiness Setup > E business setup window will be appear > Refresh e-business data > Marg ERP alert window will be appear > Click on "Yes".

4. Open server file > Then Press "F10" key > Press enter key & then press page down key.