Thanks for the reply.
This is originally from an Armory wallet.
The public key X (BE) starts with a4cfb3e3
the public key Y (BE) starts with 7970a2cc
Sorry, my mistake - I meant what does the private key start with, but you've already answered that it starts with 5, meaning it is an uncompressed WIF and therefore cannot be used to recover a "3" address in Electrum.
In the key information there is the hex or base58 format (base58 starts with the 5, and that's the one I assume I have to use).
Screenshot from the armory wallet section to show:
https://i.imgur.com/idK8mVB.pngSo, note that this script from armory - P2SH-P2PK - is not the same as "nested segwit" or the P2WPKH-P2SH script that Electrum uses. As far as I am aware, Armory is the only wallet which uses this script type. By far the easiest way to recover these coins is going to be to use Armory to send the coins over to your new Electrum wallet.
Have your tried what NeuroticFish posted? It is also a good idea, to just know the validity of your private key, or if you can run bitaddress html on an airgapped device and check the private key wallet details which would let you know if it is also a valid private key or not. But using Electrum would be good and you will not also be able to import it if the private key is invalid as the next button will grey out.
This is unnecessary. We already know the WIF is valid since OP can use it to recover an empty legacy address.
Thanks for your quick reply.
The main problem I have is that my armory refuses to send out any coins. Whenever I try to send any coins I get this error:
https://i.imgur.com/I3eUAVg.pngHowever, the transaction fee is most definitely high enough. (I put it at 120 sat/B and then later even at 200 sat/B to make sure that wasn't the problem). (I have completely rebuild and rescanned armory a few times, which in the past would sometimes solve this issue but now it hasn't.)
So I am unable to send these coins from my armory, which is what I initially tried to do (I guess I could go to the armory subsection but I thought there was no longer any support for it).
Because I'm unable to send any coins from Armory I was trying to just sweep it from those addresses into my electrum wallet, which works fine for some addresses but not for this one.
I would also be happy if there is a way to get Armory working again, but for the last few years it's not been easy to work with and keeps giving me errors.