Choose Continue with Google and select the same Google account you used in the Android app. You do not need a separate MonAI username or password, and you do not need to register a new account.
Google sign-in is also available on the MonAI web login page, even when the Android app is unavailable on Google Play.
If you and a family member use separate MonAI accounts, each person should choose their own original Google account.
Check that you selected the original account rather than another Google address. An empty gallery on a different account does not establish that your old artwork was deleted.
If you still cannot find your account, contact support from MonAI's Support screen so the message includes the current User Id. Never send your password.