Stake failed RPC error

I have problems with making a stake. After selecting a validator, I get a stake failed -rpc error message What can I do?

Are you doing this in SDK? Wallet? If so, which?
What version?
What network are you trying on? Devnet? Testnet?
What is the error code?
What arguments are you providing?

Help others help you by adding more context…

Sui wallet on testnet. No error code