I have Fitbit Sense with the app on my Android phone

Nice to meet you, *****!
Could you please clarify which Fitbit Sense version?

Okay.
Let's try to make a hard reset of your Fitbit and then reconnect it again.
Don't you mind?

In the following messages, I will provide you with step-by-step instructions. I would be grateful if you could tell me when you complete every step.

Press and hold down the solid state button on your Sense for 10 seconds if it's frozen. At first, it will look like nothing is happening, but keep holding the button down. After 10 seconds, the Fitbit logo will display, and your watch will restart.

Good.
Open the Fitbit app on your phone.

Click on the little avatar photo in the top left corner.

Click on the "Set up a device" button.

Select your version.

What do you see on the screen now?

Click on the "Yes" or "Accept".
It depends on which option it offers.

Now click "I accept".

Now you need to take your Fitbit to charge.

What do you see in the app at the moment?

Okay.

Yes, select it.

Do you see it on the Fitbit screen?

No, no. It's code to connect your Sense.

A 4-digit code should be on your Fitbit Sense screen.
And you need to enter this code in the Fitbit app on your phone.

What do you see on the watch screen?

Does your Sense show anything?

That's okay.
Don't you see the code on the watch?

Is it connected to the phone?

Do you mean the code?

Okay. So the issue is solved?

If your watch is connected now, you don't need a code.

Okay.

Could you please clarify which phone you have?

Please try these other steps to see how your Sense responds:

1. Remove your Sense from the Bluetooth settings.
2. Check if the Fitbit app is updated.
3. Force quit the Fitbit app and reboot your phone.
4. Open the Fitbit app and log back in to your account.
5. Pull down on the screen to force a manual sync.
6. Try using the Google Assistant app on your Sense one more time.

From the phone settings.

Alright.
Now you can try to pair it again with the instructions I sent you earlier.

Could you open the Bluetooth settings and delete Sense from there?

Yes.

Good. Try to repair it again.

I meant to pair it again. In the same way, I sent you earlier.

Here are the instructions:

1. Open the Fitbit app on your phone.
2. Click on the little avatar photo in the top left corner.
3. Click on the "Set up a device" button.
4. Select your version.
5. Click on the "Yes" or "Accept".
6. Now click "I accept".
7. Take your Fitbit to charge.
8. Enter the 4-digit code.

I'd recommend giving a try to the following:

1. Turn off the Bluetooth in your phone and any other device nearby.
2. Force quit the Fitbit app.
3. Reboot your phone and restart your watch.
4. Turn on the Bluetooth only on your phone and open the Fitbit app.
5. Tap your profile picture > Set Up a Device > Sense > Replace Device.
6. Follow the onscreen instructions and if prompted, accept to pair your watch with your phone.

You need to open task manager on your phone  and close it from there

You don't need to open settings to do that

Tap the. Recent Apps icon.  to view recent apps.
Perform any of the following: Open: Scroll to and tap the desired app in the list. Close: Scroll through the list of apps, hold the app then swipe the screen up.

Noted, it means that the app is closed

Sure, you don't need to delete it
You can proceed with the rest of the instructions

1. Turn off the Bluetooth in your phone and any other device nearby.
2. Force quit the Fitbit app.
3. Reboot your phone and restart your watch.
4. Turn on the Bluetooth only on your phone and open the Fitbit app.
5. Tap your profile picture > Set Up a Device > Sense > Replace Device.
6. Follow the onscreen instructions and if prompted, accept to pair your watch with your phone.

Press and hold the button or buttons on your tracker for 5 seconds. Release the button. When you see a smile icon and the tracker vibrates, the tracker restarted.

To restart your watch, press and hold the button for 10 seconds until you see the Fitbit logo on the screen, and then release the button.

Great! Now turn on the Bluetooth only on your phone and open the Fitbit app.

I’m glad I was able to get that sorted out for you. Is there anything else I can assist you with today?