The missing sourceId error occurs when you did not specify an Id for the placeholder you are inserting:
When you're adding placeholders, there's a "source ID" field you need to set (it might be hidden by a scrollbar). That field should be unique to each different type of data source you are inserting. So, for example, if you're creating a report for only Facebook data, then that source Id should always be "1". But if you wanted to create a report for two Facebook accounts, then you would use two different source Ids, perhaps "1" and "2" -- this lets Sparrow know which source we should map the placeholder you are inserting to (either the first Facebook page or the second).
Source Ids have to be unique as well - so you can't insert a Facebook placeholder with id "1" and an Instagram placeholder with id "1".
Similar to the "Missing SourceId" error above, if you see an error message about a missing contentId, you are missing another unique identifier.
Something Went Wrong
This can sometimes happen due to connection issues, missing contentId, or simply because of a bug we haven't caught yet. If you run into this issue, feel free to message us on live chat, and we can help troubleshoot.
Element already used
The above error can occur when you try and use the Use Selected as Placeholder button on a page element that already a Sparrow placeholder:
To resolve this issue, simply click the Insert Metric button instead, or select a different textbox that is not already associated with a Sparrow placeholder.