I had this trouble a few months ago and now it is happening again! My device won't even recognize my internet. The last time this happened, I put in a support ticket. They emailed me back and asked for information from my device. I sent a picture of the device tag with everything support would need to identify my device but I kept getting responses back saying I hadn't provided the requested information. Get it together and fix the problems! Your customers deserve better!!
You say "again" but this is your first post (out of five) that mentions your having this issue. That means we have no history about what was done. So, we're starting from scratch.
What device do you have? Does it support 2.4 GHz and 5 GHz networks? If you don't know, give us the model number and we can tell you. Settings > System > About
You see, on 2.4 GHz networks, where the user has a router provided and maintained by the ISP, the user sometimes finds the ISP has changed the settings to something that interferes with the connection. Users can usually fix that. If your ISP is Comcast/Xfinity, for instance, this is likely. Other ISPs are doing this too.
If your device is only connecting on 2.4 GHz networks, your router must be set to b/g/n. Comcast/Xfinity is notorious for changing that setting to g/n which stops Roku from properly connecting.
Also, some ISPs have actually turned of the 2.4 GHz networks.
So, what is your Roku model number (number is what we're after)? And what is your ISP, and does your ISP provide and maintain your router?
DBDukes Roku Community Streaming Expert Note: I am not a Roku employee.
If this post solves your problem please help others find this answer and click "Accept as Solution."