Hi Micha3615,
Thank you for using the Xerox forum.
I would suggest that you review the following solutions on our support site.
Solutions for : No Changes to Apply Message and Setting Will Not Apply in CentreWare Internet Servic...
Based on the second solution it seems there could also be a cause that requires contacting our specific product support experts at the following link: Fast Track to the Expert
Our client have about 10 Xerox, all different model but configured the same way. We have an issue with the Xerox 5745, it doesn't save the SMTP server address, or DNS name at all. You enter the information and then once you've applied it and go back to check the settings it's all gone.
It did work up to last week and now it doesn't, rebooted the printer still the same issue. Nothing has changed other than this.