My GRP2603P forgets the contact list.
This list is loaded in .xml file




Can you explain your issue in brief.


I manually upload the contact list in .xml format, but after a day or if the phone rebbots it loses that contact list


the phone alone does not lose the customizations, it could be that you have some provisioning that overrides the settings when you restart,
check with your supplier or ask for Grandstream assistance at the link written above