If your phone cannot connect to Fi's servers due to poor LTE-M/Wi-Fi, you will see a banner at the bottom of the Live Tab that indicates Poor Phone Signal - (your dog's) location data is delayed.
This alert is related to your phone's ability to receive data, not to Fi Collar's performance:
If there is a Wi-Fi network available, we recommend connecting to Wi-Fi to improve your phone's connectivity. You can learn more about improving connectivity here.
If you are in a location with poor LTE-M (meaning poor cell service), we recommend keeping a close eye on your dog, as you may experience delays in remote tracking.
Once you are in a location with improved GPS, LTE-M and/or Wi-Fi, this alert will automatically disappear.