Please check to see if your phone is connected to Loomo via hotspot mode. While in hotspot mode, your phone will not be able to access the Internet. Therefore the Loomo app will display a fail-to-connect notification when you conduct operations that require Internet access such as logging in/out or uploading/ changing your profile picture.
If you would like to change your profile picture or log out, please connect to Loomo via Wi-Fi mode instead.
For more information, please refer to the FAQ topic: "Can my phone access the Internet when connected to Loomo via hotspot mode?"