> my firebird instance is stop working sometimes. Everytime it happens, i h=
> ave to manually restart both fb guardian and fb server.
>
> on the logs i found the error:
>
>
> XNET Error get_free_slot() failed
>
>
> any ideia of what could be the issue?

Upgrade to the latest release (2.1.3 or 2.0.5). Search Release Notes (or tracker)
on how many such bugs was fixed.

Regards,
Vlad