If you have changed your mail server you need to update the following in Palette. To be able to change this you need to have access to your application server. This is recommended to be done by someone with technical experience.

On the application server, under the file structure for the Palette installation you should find a folder named BMS or PAMS. There you should find a file called Palette.Baltzar.Interface.Winservice.Maintenanceserivce.exe.config or Palette.P2P.Application.WinService.Arena.MaintenanceService.exe.config depending on your Palette version.

Before editing the the file, it is recommended to make a copy of the file in case something goes wrong.

Open the file with notepad and find the tag <add key="SMTPServer" value="%smtpserver%"/>

Change the value to the new mail server and save the file. After saving the file, restart the PaletteArena Maintenance Service, the Palette Windows service located on the application server or SQL-server. 

For information how to restart the PaletteArena Maintenance Service, see the Solution: How do I restart the PaletteArena Maintenance Service?