My streaming apps like CALM Radio and TuneIn drop the signal after just a few minutes. These work fine on other devices, so suspect it must be the unit. Support for these apps confirm their streams are solid.
Solutions...?
Is it happening with every channel on your Roku, or only one or two? If it's only certain channels, then it's not likely a Roku issue. Remember that Roku does not create the channels you are using for those providers. And the apps on other devices are written in a completely different programming language, so you can't compare how they work on different devices.
If only those channels have issues, you need to contact the provider of the channels. In your case those channels are developed by the providers, so the first place to check is their web sites for product support.