If you try and purchase BNB through the Trust Wallet or another exchange or intermediary such as Kraken, Paybis, Crypto.com, Binance, etc. and get an error, it's most likely due to your location. Those in New York and California are unable to purchase BNB directly.
If you run into a problem when purchasing on Pancakeswap it is most likely due to an incorrect slippage rate. Be sure that it is set to 12%.
If you notice that after you attempt to swap BNB for Thropic and are taken to the Trust Wallet and nothing happens, reconnect your wallet using the Chrome browser app. There is a bug affecting some Trust Wallet users using Safari where your wallet does not fire a confirmation screen.