Hi I'm trying to get a contract verified on polygonscan. But am getting this error:

ParserError: Source "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/ERC721.sol" not found: File import callback not supported
 --> myc:3:1:
3 | import "https://github.com/OpenZeppelin/openzeppelin-contracts/blob/master/contracts/token/ERC721/ERC721.sol"

Does anyone know how I get around this? I'm pretty sure I'm doing everything else right

1 Answer 1


you can use flattener plugin in remix to get one single file. The chains don't recognize these imports so better create single file and then verify, also make sure you are setting the compiler version same as what you deployed with.

  • Thanks, I'll try this and follow up in the thread if it works Commented Mar 7, 2022 at 16:55

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