It’s organized from quickest wins to deeper fixes.

1) Two Golden Rules: Same Network & No Isolation

• Put your phone and Roku on the exact same Wi-Fi SSID (not a guest network).

• In your router, disable AP/Client Isolation (sometimes “Wireless Isolation”). This feature blocks device-to-device traffic the app needs.

2) Quick Resets That Solve Most Cases

• Restart phone (or toggle Airplane Mode for 10 seconds).

• Reboot Roku: Settings → System → Power → System restart (or unplug for 10–15s).

• Power-cycle router and wait two full minutes after it comes up.

3) Enable Roku’s Mobile App Control

On the Roku: Settings → System → Advanced system settings → Control by mobile apps → Network access → set to Default or Permissive.
While you’re there, open Settings → System → About and note your Roku’s IP address for manual connection later.

4) iPhone/iPad Fixes

• iOS Settings → Roku → Local Network → On.

• Enable Background App Refresh for Roku.

• Under your Wi-Fi network (tap the “i”): temporarily disable Low Data Mode and Private Wi-Fi Address to rule out isolation quirks.

• If issues persist: delete & reinstall the app, then reboot the iPhone.

5) Android Fixes

• Battery optimization: Settings → Apps → Roku → Battery → set to Unrestricted (naming varies by brand).

• Permissions: grant Nearby devices and, on some versions, Location.

• Storage: Clear Cache (and Storage if needed) for the Roku app.

• Temporarily remove VPN/DNS apps and retest.

6) Make Your Roku Discoverable (Power & Sleep)

• Roku TV: enable Settings → System → Power → Fast TV Start so the app can wake/find it.

• Players (Stick/Ultra): turn off Bandwidth Saver (Settings → Network) to avoid sleep-like behavior.

7) Fix Your Wi-Fi Environment

• Avoid guest SSIDs; they usually block peer traffic.

• If you have separate 2.4 GHz / 5 GHz SSIDs, put both devices on the same band (start with 2.4 GHz for reliability).

• On mesh systems, test near the same node or temporarily turn off band steering.

• In router settings, try toggling IGMP Snooping / Multicast (helps discovery on many models).

• Ensure the router firewall isn’t in High/Strict mode for LAN-to-LAN traffic.

8) Manually Add the Roku by IP (Bypasses Discovery)

In the Roku app: Devices → ⋯ → Connect Manually → enter the IP address you noted earlier.
If this works, discovery (multicast) is the problem; keep router/permission tweaks from step 7/4/5.

9) Special Connection Scenarios

• New Wi-Fi or password change: reconnect Roku to the new network with a physical remote first; the app can’t help until Roku is online.

• No remote + new network: create a phone hotspot with the exact old SSID/password so Roku auto-joins; then update Wi-Fi in Roku settings.

• Hotel/dorm Wi-Fi with captive portal: use Hotel & Dorm Connect during wireless setup before trying the app.

• Office/campus Wi-Fi: many block device discovery entirely; use a personal travel router or a shared hotspot.

10) When It Connects but Controls Are Glitchy

• Confirm you selected the correct Roku under Devices.

• If audio is missing or odd, toggle Private Listening off/on.

• Close heavy downloads/streams on the network; upload saturation often causes remote lag.

• Allow microphone/keyboard permissions for voice and typing features.

11) Update Everything

• Roku OS: Settings → System → System update → Check now.

• Roku app: update from App Store/Google Play.

• Router firmware: outdated builds break multicast and LAN discovery.

12) Rapid Triage Map

• Works on a phone hotspot but not home Wi-Fi → your router settings are blocking discovery.

• Manual IP works but auto-find doesn’t → multicast/permissions issue.

• Neither works → re-verify same SSID, Roku online status, and VPN/firewall toggles.

Prevention Tips

• Keep Fast TV Start enabled (Roku TV).

• Reserve a DHCP IP for Roku in your router to make manual connects predictable.

• Avoid guest/isolation SSIDs for media devices.

• Reboot older routers periodically and keep firmware current.

Bottom Line

Nearly How to Fix Roku Remote App, missing permissions, or sleep states. Match SSIDs, disable isolation/VPNs, enable mobile app control, grant iOS/Android permissions, and—if discovery still fails—connect by IP. This sequence restores control in the shortest path.