We're sorry to hear that you're having trouble logging into Snapchat on your Android device :(
Here are a few things you can try to get into your account:
Make sure you're using the official Snapchat app from Google Play on your Android device.
Check that your system clock's date is correct on your device.
Confirm that you have a valid Google Account on your Android device:
If you do not have a Google account on your Android device, please add or create one.
If you do have a Google account on your Android device and are still experiencing this issue, please double check whether your Google account is valid. Go to Settings > Accounts > Google on your Android device. If your Google account is no longer valid, you will see a "Sync error" message similar to the image shown below:
This issue is most commonly caused by changing your Google account's password from another device, you can fix this by following the instructions here.
Hope this helps!