Halo.
I have BookIt 2.0.5.
If I have to administrate reservation from frontend reservation is not visible. In backend is possible and running.
Can help me?

Hello,

I tested it and it should work.

What you can check:
1. Check customers and your admin account should be not there. It you find him there, remove him.
2. Is your admin account Super User? If not, check permissions for your user group. You can find Permissions in Configuration.
3. Is your admin set as admin in Booking component?

1nd point helps, I see reservations in frontend.
but
Error:BookingModelCustomer->setIdByUserId(): user with id 344 isn't active customer or admin

Ok, this will be problem with point 3. Your account is neither set as customer nor as admin (manager). Go to Components -> ARTIO Booking -> managers and find your account. If you get mouse over right column, it should write "Unset from Global Managers".
If it writes "Make Global Manager", then click on it.

My account is set as global manager.

Hello,

Do you have still problem? I tested it for sure and if I am logged in as Global Manager, this message disappear.