# Error verifying ERC721 in Etherscan "Error! Unable to generate Contract ByteCode and ABI" **URL:** \ **Category:** Smart Contracts\ **Tags:** erc721, etherscan-verify\ **Created:** [December 22, 2021, 5:11am UTC](https://forum.openzeppelin.com/t/error-verifying-erc721-in-etherscan-error-unable-to-generate-contract-bytecode-and-abi/21405 "2021-12-22T05:11:10Z")\ **Posts on this page:** 8\ **Page:** 1
**Author:** ![noFAYZ](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/nofayz/32/11601_2.png) [@noFAYZ](https://forum.openzeppelin.com/u/noFAYZ)\ **Post date:** [December 22, 2021, 5:11am UTC](https://forum.openzeppelin.com/t/error-verifying-erc721-in-etherscan-error-unable-to-generate-contract-bytecode-and-abi/21405/1 "2021-12-22T05:11:10Z")
Hi, Followed the steps here: [Error verifying ERC721 in Etherscan: File import callback not supported with GitHub imports - #11 by abcoathup](https://forum.openzeppelin.com/t/error-verifying-erc721-in-etherscan-file-import-callback-not-supported-with-github-imports/4198/11)? Successfully Flattened the source code. but i'm getting the above error while verifying. ---
**Author:** ![asmel](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/asmel/32/11994_2.png) [@asmel](https://forum.openzeppelin.com/u/asmel)\ **Post date:** [December 22, 2021, 5:57am UTC](https://forum.openzeppelin.com/t/error-verifying-erc721-in-etherscan-error-unable-to-generate-contract-bytecode-and-abi/21405/2 "2021-12-22T05:57:36Z")
could share your contract ---
**Author:** ![noFAYZ](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/nofayz/32/11601_2.png) [@noFAYZ](https://forum.openzeppelin.com/u/noFAYZ)\ **Post date:** [December 22, 2021, 6:48am UTC](https://forum.openzeppelin.com/t/error-verifying-erc721-in-etherscan-error-unable-to-generate-contract-bytecode-and-abi/21405/3 "2021-12-22T06:48:20Z")
Contract: > **[Contract Address 0xf0401f774b453c551974222d3224347ce9d3e4f7 | Etherscan](https://etherscan.io/address/0xf0401f774b453c551974222d3224347ce9d3e4f7)** > > The Contract Address 0xf0401f774b453c551974222d3224347ce9d3e4f7 page allows users to view the source code, transactions, balances, and analytics for the contract address. Users can also interact and make transactions to the contract directly on... Code: [https://gist.githubusercontent.com/noFAYZ/5e3087063659deb73d86331b985a477f/raw/0fe63e14da4b65543a755dea8dd7d5ad00ff8cfa/MetaAngelDAO](https://gist.githubusercontent.com/noFAYZ/5e3087063659deb73d86331b985a477f/raw/0fe63e14da4b65543a755dea8dd7d5ad00ff8cfa/MetaAngelDAO) ---
**Author:** ![Amxx](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/amxx/32/668_2.png) [@Amxx](https://forum.openzeppelin.com/u/Amxx)\ **Post date:** [December 22, 2021, 8:44am UTC](https://forum.openzeppelin.com/t/error-verifying-erc721-in-etherscan-error-unable-to-generate-contract-bytecode-and-abi/21405/4 "2021-12-22T08:44:02Z")
> [@How to verify a contract on Etherscan/BscScan/PolygonScan](https://forum.openzeppelin.com/t/how-to-verify-a-contract-on-etherscan-bscscan-polygonscan/14225): > > Make sure to read this post before asking a question about verification. If your issue is not addressed here, just leave a comment below. If you want to pay someone to do the verification for you, create a post in #Smart Contracts > Developer Wanted. This guide applies to [all Etherscan instances](https://etherscan.io/eaas), including all of the following as well as their testnet explorers: [etherscan.io](http://etherscan.io) (Ethereum) [bscscan.com](http://bscscan.com) (Binance Smart Chain) [polygonscan.com](http://polygonscan.com) (Polygon) [snowtrace.io](http://snowtrace.io) (Avalanche) Recommendations Prac… ---
**Author:** ![faisal750](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/faisal750/32/11508_2.png) [@faisal750](https://forum.openzeppelin.com/u/faisal750)\ **Post date:** [December 22, 2021, 9:48am UTC](https://forum.openzeppelin.com/t/error-verifying-erc721-in-etherscan-error-unable-to-generate-contract-bytecode-and-abi/21405/5 "2021-12-22T09:48:44Z")
Can someone help me Verify my ERC20 Token Smart Contract? i am really battling. ---
**Author:** ![noFAYZ](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/nofayz/32/11601_2.png) [@noFAYZ](https://forum.openzeppelin.com/u/noFAYZ)\ **Post date:** [December 22, 2021, 11:43am UTC](https://forum.openzeppelin.com/t/error-verifying-erc721-in-etherscan-error-unable-to-generate-contract-bytecode-and-abi/21405/6 "2021-12-22T11:43:11Z")
@Amxx I'm following the same steps. i did flatten the contract but its still not verifying ---
**Author:** ![asmel](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/asmel/32/11994_2.png) [@asmel](https://forum.openzeppelin.com/u/asmel)\ **Post date:** [December 22, 2021, 1:44pm UTC](https://forum.openzeppelin.com/t/error-verifying-erc721-in-etherscan-error-unable-to-generate-contract-bytecode-and-abi/21405/11 "2021-12-22T13:44:22Z")
I'm going to check your code. Since I had seen many problems when verifying the erc721 token and most of it has to do with the parameters passed by the constructor. My recommendation is after you flatten the contract, modify the constructor parameters, and declare those parameters inside the constructor directly, and I recommend checking in the testnet before doing it in the main one. ---
**Author:** ![asmel](https://sea2.discourse-cdn.com/flex022/user_avatar/forum.openzeppelin.com/asmel/32/11994_2.png) [@asmel](https://forum.openzeppelin.com/u/asmel)\ **Post date:** [December 22, 2021, 3:56pm UTC](https://forum.openzeppelin.com/t/error-verifying-erc721-in-etherscan-error-unable-to-generate-contract-bytecode-and-abi/21405/12 "2021-12-22T15:56:31Z")
this is the contract flattened and verified on the rinkebay network 0x5bDC6c6383aeb43892aC0eF7aD1F6C85DC9F7C30 You can take the code from the verification, as you can the parameters in the main construct, they were changed to their respective contract in this case it is the contract that is named ERC721, I also recommend that you practice deploying in the test network and then in the main one Another recommendation is that the symbol of your contract does not exceed 9 characters > I hope this helps you Sincerely asmel