This article covers 

I am not able to save a change in account mapping in Xero.

Unable to change account mapping under manage mapping.

Summary

While trying to change an account mapping under manage mapping in Xero/QBO in CB, the save button on top is greyed out, and hence not able to save the change. This usually happens when one of the fields on the page is left unconfigured.

Solution

When you go in to edit the mapping after setting up the integration, you will need to configure each and every setting in order to save the change i.e. any one of the options is unconfigured as shown below, you would not be able to save the changes that you made. 

You would need to select an option for these as well and configure these and only then will you be able to save the changes made.