My plugin Appointments+ has an error code

I have a weird error code on my page "Request an Estimate", wondering how to get rid of that... this is the code I used before that I copied and pasted from a friend a while ago:

[su_spoiler title="Request a Call" style="fancy" class="my-custom-spoiler"]

[inbound_forms id="138" name="Request an Estimate"]

[/su_spoiler]

[su_spoiler title="Schedule Your Estimate" style="fancy" class="my-custom-spoiler" open="yes"]

[app_services autorefresh="1"]
[app_service_providers empty_option="Select Service Provider" autorefresh="1"]
[app_monthly_schedule]

[app_monthly_schedule add="1"]

[app_pagination month="1"]
[app_confirmation button_text="Book Appointment!"]

[/su_spoiler]