Issue with extracting data for multiple api calls in custom data connector

I'm trying to extand data using a custom data connector, but I got an error that type Record can't be convert into type Table. Can anybody give me some advice what I did wrong. Here is my code.

getMydata.getMyData = (apiKey as text, symbols as text, startYear as text, endYear as text) =>
        let
            symbolList = Text.Split(symbols, ","),
            initialPosition = 0,
            getJson = (position) =>
                let
                    source = Json.Document(
                        Web.Contents(
                            "https://myDataAPI.com/getData.json?apikey="
                                & apiKey
                                & "&symbol="
                                & symbolList{position}
                                & "&startYear="
                                & startYear
                                & "&endYear="
                                & endYear
                        )
                    ),
                    apiData = try source[results] otherwise null,
                    data = if apiData <> null then apiData[data] else null, // extract "data"
                    toTable = if data <> null then Table.FromRecords(data) else null 
                in
                    toTable,
            AllJson = List.Generate(
                // initial
                () => [i = 1, data = getJson(initialPosition)],
                // condition
                each [i] <= List.Count(symbolList),
                // next
                each [i = [i] + 1, data = getJson([i])]
            )
            ,
            toTable = Table.Combine(AllJson) // combine all tables into one
        in
            toTable,