Hello @Japheth and welcome to the Community. You wrote Flex smartwatch, but the Flex is a older model tracker on Fitbit's Legacy Device List. Can you please verify which model Fitbit you have? Your post can get moved to a better fit forum for your issue. Your phone looks like it meets the minimum requirements and isn't on the list of specific phones with problems.
Laurie | Maryland
Sense 2, Luxe, Aria 2 | iOS | Mac OS
Take a look at the Fitbit help site for further assistance and information.
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