1. Token approval/Allowance issues (the most common)

The contract you are interacting with has not obtained your token transfer approval, or the approval limit is insufficient, or the approval has expired. The contract will revert and roll back on the first step of execution.

2. The contract itself is broken/running away/Rug pull
On the BSC chain, many scam tokens, Ponzi schemes, and fund projects, after the project team runs away, the contract will be paused, permissions to destroy it will be revoked, blacklisted, or functions will be locked, and any call will directly result in an error and failure.

3. The contract has set an address blacklist
Your wallet address has been blacklisted or restricted from interaction by this third-party contract, directly prohibiting your address from calling any functions.

4. Abnormal slippage/anti-sniping settings
Your anti-sniping is currently Off. Many swap and trading contracts have no anti-sniping or have very low slippage. On-chain pre-verification will directly determine the transaction as destined to fail, intercepting it early and preventing you from submitting.

5. The token itself has transaction taxes/transfer restrictions
Most scam tokens on BSC have buy/sell taxes, holding thresholds, and transaction snapshots. If you do not meet the holding rules, you cannot call the contract.

6. Wallet RPC node failure
The default BSC node of your wallet is lagging or out of sync, causing simulation of transaction execution to error out, which is not an actual on-chain problem.

7. Unknown high-risk malicious contract
The wallet cannot identify what this transaction is supposed to do (unknown transaction type), most likely a malicious contract that steals tokens through approval or drains assets with unlimited allowances. The wallet actively intercepts and locks the confirmation button to protect you. $BTC