Welcome to the Fitbit Community, @j_sun. I am sorry for the delayed response.
I appreciate your participation in the Forums and sharing that your iOS app will randomly log you out every couple days. Thanks for trying to resolve this and I am here to help. I recommend doing the following:
- Manually log out from the Fitbit app.
- Verify if the Fitbit app is updated to the latest version. For instructions, see this help article.
- Force quit the Fitbit app.
- Reboot your phone.
- Open the Fitbit app and log back in to your account.
Please monitor the app after that and see if the issue gets fixed.
Keep me posted on the outcome. I'll be around if you have any additional questions.
Want to discuss ways to increase your activity? Visit Get Moving in the Lifestyle Discussion Forum.
