If you're having issues with PlayStation Remote Play, start here:
1) Ensure you've completed the setup instructions for PS Remote Play here.
*Please note: You will need to complete the initial setup on the same network as your console.
2) Double check your phone and PlayStation Remote Play app are both up-to-date.
3) Make sure your console is on or in rest mode.
4) Check your console's network connection: Go to Settings > Network > Connection Status > Test Internet Connection
5) Perform a network speed test on your device. The minimum required connection speed for Remote Play is 5Mbps for both upload and download, but 15Mbps or faster is optimal for the best experience.
6) Use 5Ghz Wi-Fi or Ethernet. While 2.4Ghz networks will work, it’s not optimized for game streaming, even if the speeds are adequate.
7) Reinstall the PS Remote Play application on your device.
8) Lower Remote Play resolution for PS4 Remote Play (PS4 only): You can change the PS4 Remote Play application video quality to improve your connection. From the launch screen of PS Remote Play on your device, go to Settings > Video Quality for Remote Play. Set Resolution to Standard or Low, and Frame Rate to Standard.
9) If you continue to experience any issues getting set up for Remote Play, please contact the PS Support team here.