Not work (void-function cider-default-connection)

I have a `FlyC!` 
_(documentation: The last syntax check failed. Inspect the \*Messages\* buffer look for error messages, and consider reporting a bug.)_ 

so in the \*Messages\* buffer: 
```
Error while checking syntax automatically: (void-function cider-default-connection)
```

Maybe is a `cider` problem, thanks in advance.