Thanks for the post.
Please be advised that we only support English in the Roku Community. We had to use google translate to understand your inquiry.
Regarding your concern, if you are getting an error code or message, refer to this link for common Roku error codes and their recommended actions: What should I do if I cannot connect to my home network or the internet?
Furthermore, please note that Roku Express is only compatible with wireless b/g/n networks on the 2.4 GHz spectrum. Ensure that your router is broadcasting a 2.4GHz Wi-Fi network for the device to connect to. You can check your device model by navigating to Settings > System > About or underneath the player itself. You can also try configuring your router and use wireless channels 1, 6, or 11 which are the preferred channels in North America. Each time you change the wireless channel, you will likely need to apply/save changes before you are prompted to restart the router.
Let us know how it goes!
All the best,
Roku Forum Moderator