What is the message transaction check failed?

The message "Transaction check failed" indicates that MWEB is activated but no MWEB transaction exists in your blockchain.

You can resolve this by creating an MWEB transaction with your wallet with the following instructions.

Open your wallet.

Press on the button "Receive".

Select the option "Generate MWEB address".

Press on the button "Create new receiving address" to create a new receiving address.

Press on the button "Copy Address".

Press on the button "Send".

Enter the copied MWEB receiving address after "Pay To:"

Enter the minimum amount of coins (0.0001) you want to send after "Amount:"

Press on the button "Send" to send the transaction.

Follow these additional steps when you see the message "Warning: Fee estimation is currently not possible."

Press on the button "Choose..."

Select "Custom".