The most common reason for not being able to successfully complete transactions is an "Insufficient gas fee" error. Every action on the Sui network requires a small amount of SUI to process. If your wallet doesn’t have enough SUI available, the transaction will fail. Additionally, if you are swapping tokens, the transaction might fail if the price moves too quickly (slippage). Always keep at least 0.1 SUI in your wallet to cover future network fees.
Another common error is the "Transaction is rejected as invalid by more than 1/3 of validators" error. The following error means that you tried to use the same objects in multiple transactions at the same time. When the same object is used in multiple transactions at the same time, it can result in the object getting locked for the remainder of the epoch. It should resolve itself at the end of the current epoch (epochs take 24 hours).