Still stuck...

[o_e_l_e_o]

I did what you advised and both devices showed 6 different numbers.

Have you tried using these new 6 digit codes generated by your second device to access the accounts in questions?

Does the 16 digit key need to be in capitals or lowercase?

It shouldn't make a difference since they are Base32 strings, but I suppose it depends if you are using a buggy app. I have always seen them displayed as all uppercase, though. On Aegis, it doesn't matter if you enter lowercase or uppercase, they both generate the same 6 digit codes.

[Krytokee]

Thank you for your help. Sadly none of it worked.

[khaled0111]

I did what you advised and both devices showed 6 different numbers. So there has to be an issue with the 16 digit secret key.

Did you compare the generated codes on both devices at the same time? The generated codes are temporary and change every 30 seconds or so. If you get different codes then one or both your devices are out of sync (assuming you you imported the correct secret key).
Since those codes are temporary, you have to enter the generated code on bittrex, or whatever service you want to access, before it expires or it will become invalid.

[Bitfort]

... The title he used above the key was underlined Bitrexx Secret Key...

According title wording I would assume these are API keys (not 2fa backup codes). But it's weird they are single strings (these should come in pairs) and 16 chars is quite short ... so I guess this is not a valid point.

last desperate hints:
Maybe your uncle mistakenly swapped those two backup codes. Try using 6 digit code generated from bittrex backup to login into coinbase.
In past I had 2fa sync issues on my old device. Couple times worked using the expired 6 digit code. Try writing down current 6 digits, wait till new set of digits is generated and try to login using the old ones.

[CryptocurencyKing]

Should you @OP be having the 16digit codes correctly which comes mainly all in upper case, you shouldn't be experiencing q lot of difficulty as you seem to specify. It simply should work on any device at all.

All that is expected of you is to download and Authenticator app and then, using your 16 digit code to import the authentication sequence for a specific account though, having 2 variant codes code mean an error for you because, each could belong to a separate wallet and you can interchange then so, I suggest you do a trier and error move towards each. What I'm saying in essences is,

Let's say, you've got account 1&2 and it's 16 digit verification code for importing the sequence on Google Authenticator. You,
1. Proceed with the import
2. Synchronise your Authenticator time to be the same with your device and then
3. You login to the accounts 1&2 individually and try the 2fa codes generated on both at intervals.

Repeat the same procedure on both accounts while using 16 digit verification codes 2. This is just to ensure that, there isn't a swap so, its a giving the benefit of the doubt kind of thing.

[Krytokee]

HI again,

I can't thank you enough for all your help again.  This has been an interesting journey so far and ive learned so many things i never knew before.  I have read your comments religiously and tried everything to the best of my ability but i realize something is still not working - i'm not too sure if it ever will, being honest. I broke the secret key apart last night - making sure that the letters can not been mis read or mistaken but i'm confidant its ok and clear.   This has become a personal quest i want to beat regardless of any value at the end at all.  It's not about that.  I want to continue it. 

Can i personally ask a few questions though? What is there was no Secret key?  What if i didn't have that piece of paper with those details at all? Would this have been impossible then?

I watched loads off You Tube videos on back up codes.  Loads of them!!  Can i try to to access those codes?  Would they aid me? If so, would that generate a new secret key?

Thank you for all your help. I know i wouldn't have got this far with out you.

K

[o_e_l_e_o]

Can i personally ask a few questions though? What is there was no Secret key?  What if i didn't have that piece of paper with those details at all? Would this have been impossible then?

If someone loses the 2FA to their account, then generally the only way to have the account unlocked is contact the exchange and go through their recovery process, which usually involves verifying your ID. If it were any easier than this to remove the 2FA without having access to the account, then the 2FA doesn't provide any additional security, since an attacker could just request for it to be disabled.

If your uncle's accounts are locked with 2FA, and no one can access the 2FA, then your only other option is to contact the exchange in question and provide the legal documents they request as I explained in an earlier post in this thread.

This is all assuming those 16 digit "secret keys" are indeed his 2FA back up codes, but there is nothing else they really could be.

If so, would that generate a new secret key?

You cannot reset his 2FA or generate any new back up codes without first having access to his accounts.