Creating a REST API file with App Skyvia to back up Jira

[Jon]

Im trying to create a back up with the add on Skyvia which backs up changes made and if there was ever something that needed to be undone it supposedly would restore the changed to what the issue was at the time of the back up. 

However when i do the backup i get an error message on the Skyvia site saying the below. What screen is skyvia trying to make these changes on? I have checked all the different screens and made sure that all the fields are on each  each screen so i dont know what could be going wrong. 

Is there some type of security setting or something else that would have to be done for it to work? 

""customfield_10019"": ""Field 'customfield_10019' cannot be set. It is not on the appropriate screen