Any chance your Roku account was originally created in another country? That would block access. Another might be if you're running a VPN.
It sounds like you may have created a Roku account that isn't located in your current region. If a channel isn't appearing in Search, it may indicate that your device is linked to an account that was created in a different region where that channel may not be offered by the channel provider. You'll want to make sure that you are using an internet connection located in the correct region when creating your account. You can check your IP address' reported location by visiting www.whatismyip.com - If you see an issue, you'll need to contact your ISP to help resolve any issue, then create a new Roku account in the correct region. We'd also recommend reaching out to the channel provider directly for more help and information regarding the availability of their service on the Roku platform in your area. They can also assist with any login or troubleshooting questions that you may have.
Thanks,
Danny