Error is due to the return type of your method. Change it to return IEnumerable<SourceModel> as you are getting IEnumerable<SourceModel> from database
public static IEnumerable<SourceModel> GetRecord(string ID)
{
var recs = Source.GetRecords(ID);
return recs; // no error now as you are returning list
}
solved Can not implicitly convert type IEnumerable