Warning! Error encountered during contract execution [Reverted]

[boxingYi]

Hi，dear
I have watched your video on YouTube，very amazing !
I clone dapp_token project and deploy this Dapp on my local testnet( ganache-cli ) and kovan testnet.
Everything is ok,but when i used account2 to buyTokens on website，an error occured during contract execution.

I try it again and again ,that error has always appeared（local ganache-cli and kovan testnet）

the tx url is : https://kovan.etherscan.io/tx/0x4bb9708302f4b1f14450e2184fce32dd207f55ff6e9f647618dbb3b35dcc7404

Input Data:
Function: buyTokens(uint256 _index) ***
MethodID: 0x3610724e
[0]: 0000000000000000000000000000000000000000000000000000000000000064

I don't know how to solve this problem，looking forward to your reply @gwmccubbin

[michealzorn]

@gwmccubbin your only doing the video only for you ? without helping people later