Stuttering and buffering on streams is normally due to insufficient bandwidth. Please see the Recommended Bandwidth FAQ page here (quality is based on the connection rate).
If the bandwidth is fine, exit the game and re-launch it. If that does not help, exit and then re-launch the MLB application.
If bandwidth is a problem, power cycle your router and modem to try to improve the connection. (Power cycling is turning off the power to the modem and router then powering back on, in an attempt to refresh the Internet connection.) Also, try to limit the amount of devices sharing your Internet connection as this could have an impact on your overall bandwidth.
If using a WiFi connection, you can improve your signal strength by moving your router closer to your device. Raise your router. the height of your router will usually improve its radio signal performance. Be mindful of anything that could interfere with the signal like cordless phones, baby monitors, etc. Also try limiting the amount of devices sharing your network. If you continue to have issues try connecting your Amazon Fire TV® device to your router with an Ethernet cable.
We recommend updating to the latest firmware on your Amazon Fire TV® device.
If you are having issues accessing your stream, please verify your username and password on MLB.com. Then log out and log back into your device in the "Settings" menu of the MLB app.
For any general app issues, try a hard reboot of your Amazon Fire TV® device. Remove your device from its power source for 30 seconds, then turn it back on.