You can try to uninstall the wallet completely, and then redownload it and restore it using the backup phrase you have. If the problem persists, I would suggest you open an issue on the GitHub repository[1].
I do not think the probelm will persist, the reason for my positive reply is because I have just downloaded the wallet today and it worked perfectly. The wallet generated seed phrase for me and I backup the seed phrase. I also generated a lightning network wallet on it in which it generated me also a QR code and an alternative secret code. I later deleted the wallet, redownloaded it and restored both the Bitcoin wallet I can use for on-chain transactions and the lightning network wallet successfully. It will be good for Maus0728 to delete and restore the wallet using his/her backups.
For normal Bitcoin wallet For lightning network wallet