Welcome to the forum and thanks for adding your profile picture. It helps build community! We're glad you're here. When you get a chance, please introduce yourself on this forum thread.
- When you first open Collect what version number is shown at the bottom of the menu? For example "ODK Collect v2021.3 Beta 1".
- What server (and version) are you using? For example, Aggregate or Central or something else.
- Are you the administrator of the project? If yes, can you login in normally to your server through a web browser?
- Is it just a problem with the one device? Are other devices able to submit?
- Are you trying to submit over Wi-Fi? If yes, there might be a network settings issue - can you try over a different network or over cellular data?
- Are you trying to submit large images or other media? If yes, how is your connection speed from the device? You can test with a site such as https://www.speedtest.net/
- Can you load the server from the device's web browser?