Failed to save modifications to the server - custom function

Hi Herbert,

I found "registration" in the query, and I suspect for some ids there are extra fields with incorrect data types. However, I dont see a calculation. What's the best way to send you the PBIX? Here's the offending query with modifications for privacy.

let
Source = Json.Document(Web.Contents("https://foobar.com" & meetingid & "&fromDate=" & "2016-7-1" & "&pagingCriteria.firstResultIndex=" & "0" & "&pagingCriteria.resultCount=" & "500")),
listRegistrationsResult = Source[listRegistrationsResult],
registration = listRegistrationsResult[registration],
#"Converted to Table" = Table.FromList(registration, Splitter.SplitByNothing(), null, null, ExtraValues.Error),
#"Expanded Column1" = Table.ExpandRecordColumn(#"Converted to Table", "Column1", {"email", "attendance"}, {"email", "attendance"}),
#"Expanded attendance" = Table.ExpandListColumn(#"Expanded Column1", "attendance"),
#"Expanded attendance1" = Table.ExpandRecordColumn(#"Expanded attendance", "attendance", {"entryTime", "exitTime", "durationInMinutes"}, {"entryTime", "exitTime", "durationInMinutes"})
in
#"Expanded attendance1"

Thanks

-Kevin