Strange Gateway issue

Earlier this week we upgraded our gateway to the latest version.  This morning a user contacted me stating that they could no longer select the gateway for an existing report that had previously been working fine with not changes made.

I've narrowed the problem down to a query that simply combines data from 3 other queries into a single table.  Removing this combining query resolves the issue (code below).  Does anyone know what about this query would cause the gateway to disallow access (error message below)?

let
    Source = #"LYNDA user list",
    #"Appended Query" = Table.Combine({#"Source", #"LYNDA historic data"}),
    #"Replaced Value10" = Table.ReplaceValue(#"Appended Query","M","Male",Replacer.ReplaceText,{"Gender"}),
    #"Replaced Value1" = Table.ReplaceValue(#"Replaced Value10","F","Female",Replacer.ReplaceText,{"Gender"}),
    #"Replaced Value3" = Table.ReplaceValue(#"Replaced Value1","","Not specified",Replacer.ReplaceValue,{"Gender"}),
    #"Added Custom" = Table.AddColumn(#"Replaced Value3", "Full name", each [First name] & " " & [Last name]),
    #"Renamed Columns" = Table.RenameColumns(#"Added Custom",{{"Upload Date", "Profile Creation Date"}, {"Total hours", "Hours trained"}}),
    #"Replaced Value7" = Table.ReplaceValue(#"Renamed Columns","OD","Support Services",Replacer.ReplaceText,{"Business Stream"}),
    #"Changed Type1" = Table.TransformColumnTypes(#"Replaced Value7",{{"Profile Creation Date", type datetime}, {"Registration Date", type datetime}}),
    #"Renamed Columns1" = Table.RenameColumns(#"Changed Type1",{{"Last log in", "Last login Date"}}),
    #"Changed Type2" = Table.TransformColumnTypes(#"Renamed Columns1",{{"Hours trained", type number}, {"Logins", Int64.Type}, {"Profile Creation Date", type date}, {"Last login Date", type datetime}}),
    #"Merged Queries" = Table.NestedJoin(#"Changed Type2",{"Last login Date", "User ID", "Registration Date"},#"LYNDA last login date",{"Login date", "User ID", "Registration date"},"NewColumn",JoinKind.Inner),
    #"Changed Type3" = Table.TransformColumnTypes(#"Merged Queries",{{"Hours viewed/log in", type number}}),
    #"Removed Columns" = Table.RemoveColumns(#"Changed Type3",{"NewColumn"}),
    #"Removed Columns2" = Table.RemoveColumns(#"Removed Columns",{"Group2"}),
    #"Removed Duplicates" = Table.Distinct(#"Removed Columns2", "User ID")
in
    #"Removed Duplicates"