Why MetaMask Doesn't Work for USDT TRC20
MetaMask is built for Ethereum and EVM-compatible chains, and TRON is not one of them — this isn't a bug to fix, it's a network mismatch.
TRON uses a different address format and network
TRON addresses start with T and TRON isn't an EVM chain, so MetaMask has no native way to hold, send, or receive TRC20 tokens including USDT on TRON — any attempt to do so isn't actually interacting with the TRON network at all.
What probably happened
If you were told to send USDT TRC20 and only have MetaMask, the sender likely meant ERC20 USDT instead, or you need a TRON-compatible wallet like TronLink, Trust Wallet, or one of the others covered on this site.
If you already sent funds to a TRON address from MetaMask
MetaMask can't broadcast to the TRON network in the first place, so this scenario is usually a case of double-checking which address and network were actually used — see the wrong-network recovery guide on this site for next steps.