timezone format err in google calendar API

Question

input = append(input, strings.TrimSpace(sessions[uuid]["nameStage"].(string)))
input = append(input, strings.TrimSpace(sessions[uuid]["startDateStage"].(string))+"T"+strings.TrimSpace(sessions[uuid]["startTimeStage"].(string))+"+02:00")
input = append(input, strings.TrimSpace(sessions[uuid]["endDateStage"].(string))+"T"+strings.TrimSpace(sessions[uuid]["endTimeStage"].(string))+"+02:00")


func createEvent(input []string, tok *oauth2.Token) string {

    client := conf.Client(oauth2.NoContext, tok)
    calendarService, _ := calendar.New(client)
    event := new(calendar.Event)

    // set calendar values

    event.Summary = input[0]
    startTime := new(calendar.EventDateTime)
    startTime.DateTime = input[1]
    event.Start = startTime

    endTime := new(calendar.EventDateTime)
    endTime.DateTime = input[2]
    event.End = endTime
_, err := calendarService.Events.Insert("primary", event).Do()
    if err != nil {
        log.Println(err)
        return "Cannot create event"
    }

    return "Done successfully"
}

this is a part of my code I use to create event using google calendar API .the code is written in go. the code takes the name and the time values from the session and puts it in array and sends it to createEvent sometimes the code runs correctly and sometimes it gives me an error

googleapi: Error 400: Invalid value for: Invalid format: "2018-00-18T22:08:00+02:00" is malformed at "+02:00", invalid

I use "+02:00" to make timezone Cairo/Egypt