The Neuron wallet needs to be fully synchronized with the CKB blockchain before it can accurately display any balances or assets in your wallet. If it is not synced, Neuron will not have access to an accurate representation of the blockchain, and therefore the balance may be incorrect or outdated.
If you are concerned a transaction failed, you can verify it on the CKB Explorer: https://explorer.nervos.org/
If further problems persist, it is recommended that you clear your cache (located in settings) and verify that your Neuron wallet version is the latest release.
If your Neuron wallet is still not fully synced after an extended period of time or transactions continue to fail, feel free to consult the #support channel in our Discord for further assistance. You can also view and create issues on GitHub: https://github.com/nervosnetwork/neuron/issues. If you decide to open a new issue on GitHub, we recommend adding your debug information and providing further details about your computer specs and operating system. Additionally, it is recommended that you clear your cache (located in settings), make sure that VPNs are off and computer speed is not compromised, and try restarting the application and your system.