@Anne3 You can force your POS or Terminal into Offline mode by navigating to Settings -> Hardware -> Network and disabling WiFi. As long as your Offline Mode setting is toggled on, that will usually allow you to take card payments if offline mode. Just remember to get back on a WiFi network ASAP so that you can upload payments. You only have 24 hours to do so, or you lose them.
Personally, I have all of my devices set to go into offline mode if a problem is found. Usually this happens automatically, but if not disabling WiFi on your device should work.
Of course, I’m assuming you are using either Square POS or Terminal.
Best,
