So I already went through this query, but I still couldn't get my doubt solved. Be it any Blockchain Dapp, the same error is coming for me. I used the marriage certificate and kickstart examples.
Can anyone please help me with this?
In your DApp you are probably calling some of those Web3 API functions that do publish transactions to blockchain (e.g. web3.eth.sendTransaction), or some non read-only functions of some smart contracts. And you probably didn't provide value for
from parameter, i.e. you didn't tell what private key to use to sign the transaction.
As long as every transaction has to be signed by some private key before being published into blockchain, you transactions cannot be published, and thus you get error message.
Regarding your code, your probably just don't have any accounts.