If you are working in Template Studio and find you can't save the template or preview it but also no error message is given in the "Messages" tab, Its likely the template references a field that has been marked as "Inactive" in the configuration packs.
To correct this you will need to work out what field has been marked as inactive and enable it again, Or remove the field from the template so its no longer referenced.
There is no easy way to find which field is marked as inactive, so you will just need to think back to what changes you have made in the configuration pack or ask all users what changes they have made. Once you know which fields have been marked as inactive you have open OpenGround as Administrator and go to System>Configuration Packs>select your pack>Manage Model, then find the table and field and set it as active.
After doing this you will be able to preview and save the template.