@Porfirio10
You have over 40 listings...is it happening on ALL your listings? Operating this many listings without using a PMS would be really hard? Airbnb says those using a PMS, hotels or serviced apartments must all be on the Single Fee structure.

I would check your Fee status under your Account Settings. Some Hosts have reported they don't use a traditional PMS/Channel manager, but have some automated lock software attached to their account (not the Airbnb smart lock integration) and have been told that is considered a PMS?
Account Settings
Payments
Service Fee
If it shows Host Only Fee, then go to
Account Settings
Privacy
Connected Services
See what software is connected to your account.