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Question

App stopped working with UNKNOWN_BACKEND_ERROR

  • 21 July 2024
  • 3 replies
  • 46 views

Hi everyone,

I was looking to create a custom App User Id but somehow everything stopped working all of a sudden.
I was using the account email plus a random uuid since email is said to be guessable.

This was working fine until all of sudden I keep getting UNKNOWN_BACKEND_ERROR

Complete error was this:
 {"error": {"code": 16, "message": "There was an unknown backend error. The provided app user id has been blocked. Please visit https://docs.revenuecat.com/docs/user-ids for more information. (7626)", "readableErrorCode": "UNKNOWN_BACKEND_ERROR", "readable_error_code": "UNKNOWN_BACKEND_ERROR", "underlyingErrorMessage": "The provided app user id has been blocked. Please visit https://docs.revenuecat.com/docs/user-ids for more information. (7626)"}, "target": 77}
So, I am lost. It was working fine now it isn’t.
Email alone is not advised. I can understand that.

When I make it anonymous, I can not track who is paying subscribing.
I would not know my customer accounts and if anything went wrong, I could not find any record to show my customers. So, what should I do?

I thought email + ‘_’ + uuid was a good choice but I don’t know why it stopped working.

Now the app won’t even launch it says error:16 There was an unknown back end error.

What advice can you guys give me? If you can give any.

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3 replies

joan-cardona
Rank
Userlevel 2
Badge +5

Hi @yavuzakyazici ,

 

Unfortunately even if you add a uuid after the email, the id still contains the email hence it’s guessable. The best case would be to assign a unique id to that user, set it as app user id and save that id with the email correlation in your database.

From the crash, would you be able to give us the full debug logs?

 

Best,

Joan.
Y
Badge +5

The crash was because of a mistake inside the code. So it is fine now. Thanks…

However I can not really understand how a revenuecat id is guessable when it is and email concatenated with a uuid? 
So the if the id is sth like

email = test@user.com;
uuid = VM426:2 abf37dfb-0335-4247-82ca-da710256ec31;
userId = test@user.com_VM426:2 abf37dfb-0335-4247-82ca-da710256ec31 

So how can you guess the userId?
Am I wrong?
It is created with random uuid and added to email.
Would you not have to guess the whole email + uuid?
This part is very important for me to understand.

This way I will be able to recognize the account from the email but nobody will have access unless they can guess the full id right? Where am I making a mistake?

Thanks..

Y
Badge +5

Hi @yavuzakyazici ,

 

Unfortunately even if you add a uuid after the email, the id still contains the email hence it’s guessable. The best case would be to assign a unique id to that user, set it as app user id and save that id with the email correlation in your database.

 

Hi again Joan,

The problem with this scenario is this. When I look at the Overview tab of Revenue Cat after I login, All I see will be a bunch of UUIDs. So, overview will not mean anything. To find a user, I would have to compare UUIDs. 

If I did what you suggested, storing UUIDs with email correlation to db, I would still have to compare UUID of a person with certain email. I could do this with code but still, Overview tab would be a bunch of UUIDs. So you could not tell if a certain customer has paid or not. Or you could not tell if all of your customers are on the list. You can of course check subscription status with Purchases.getCustomerInfo() ( which I am doing in the app ), I could not tell what is what when I look at the big picture. 

However, I still do not understand how someone could guess a full app user id that consists of email + uuid?  So, if you could maybe give me a hint about this I would be grateful :)

So a short answer would be appreciated.

Thanks

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