Newbie would appreciate any help

[Stuff008]

I have received a redeem script and transaction to sign on order to get a refund. When trying to broadcast the signed transaction I get the following error.. any help would be greatly appreciated as I'm lost with this..

mandatory-script-verify-flag-failed (Operation not valid with the current stack size) (code 16)

[1715049516]

1715049516

[1715049516]

1715049516

[LoyceV]

I have received a redeem script and transaction to sign on order to get a refund.

Let me ask you a question first: what service are you using, and why do you need to sign a transaction to receive a refund? This sounds very shady and might be a scam attempt. Don't sign anything you don't understand completely!

[Stuff008]

Thanks for the reply it's a multisig and already has one signature so just requires me to sign and broadcast. As I previously said I'm out my depth here but am sure there is no scams happening. Could you point me in the right direction here?

[LoyceV]

Thanks for the reply it's a multisig and already has one signature so just requires me to sign and broadcast.

Okay, so far so good.

I don't have much multisig experience. What are you using to sign? Coinb.in?

[RickDeckard]

Thanks for the reply it's a multisig and already has one signature so just requires me to sign and broadcast. As I previously said I'm out my depth here but am sure there is no scams happening. Could you point me in the right direction here?

You say that you're "out of my depth" but, at the same time, you also say that "am sure there is no scams happening" - something doesn't sound quite right to me. Please OP, before you do something that will eventually lead you here stating that you were scammed, could you stop for a moment and proceed like LoyceV said? What service are you using, what entity is asking for your signature ? Is this someone you know? Please don't tell us that you've met this "person" on Tinder and that he/she is asking for your help ...

[Stuff008]

Yes coinb.in so far I have have tried to sign the transaction hex with my electrum key then when I try to broadcast i get that error. That's as far is I have got unfortunately

[RickDeckard]

Yes coinb.in so far I have have tried to sign the transaction hex with my electrum key then when I try to broadcast i get that error. That's as far is I have got unfortunately

After some research I managed to find this reddit user[1] - which seems to have a similar problem such as yours. In this case the source of the problem was the following:

As you've discovered "16: mandatory-script-verify-flag-failed" occurs when you don't have enough signatures.

The OP of that reddit thread managed to solve his/her problem by using his bitcoin address instead of his private key of the bitcoin address. Perhaps you could try that method? He was also using coinb.in!

Again, just make sure you're not falling for any scam attempt so that you don't end up in a bad situation.
[1]https://libreddit.spike.codes/r/BitcoinBeginners/comments/c45dja/need_some_help_for_multisig/

[Stuff008]

Thanks but tried to sign the transaction with my bitcoin address and it wouldn't even sign it so back to the drawing board

[EG69]

Hello having same problem as you, tried even using my bitcoin adress and still same thing :/

[nc50lc]

That error is usually caused by signing the RAW Transaction with the incorrect private key or it's not fully signed yet (coib.in will show a result even if it's not signed by the key you've provided).

Since the tool is coinb.in, you should use the "verify" tab first before attempting to broadcast the transaction.
A ready-to-broadcast successfully signed Multisig Txn will show: a check symbol with the number of signatures under "Signed?".
You can also check the outputs(s) to see where the transaction is sending coins to (see if you're actually receiving bitcoins with that transaction).
However, that setup where you need to sign a MultiSig transaction in order to get a refund is sketchy unless explained why, you two are not the first to mention that.
I mean, why do you need to co-sign? Is their "refund MultiSig address" co-created with your public key? This doesn't make sense.

Here's another similar issue with OP sharing his discussion with the 'service': /index.php?topic=5387764.msg59399757

[LoyceV]

However, that setup where you need to sign a MultiSig transaction in order to get a refund is sketchy unless explained why, you two are not the first to mention that.
I mean, why do you need to co-sign? Is their "refund MultiSig address" co-created with your public key? This doesn't make sense.

It sounds like a multisig escrow, where each party holds 1 of 3 keys.

[o_e_l_e_o]

I've seen a couple of other users have a similar issue to this one. Invariably, it is from a darknet marketplace, which is why they are hesitant to reveal the name of the service. In addition to the thread nc50lc linked above, here is another similar one: https://bitcointalk.org/index.php?topic=5333207.0

Usually, the OP has very limited understanding of multi-sig addresses, which usually leads me to believe they set it up incorrect in the first place, perhaps by sending the service in question an xpub from a standard single-sig wallet, which then means they can't sign the multi-sig transaction.