When I try to verify my contract, I get "ParserError: Source "@openzeppelin/contracts/..." not found: File import callback not supported"

Smart Contracts
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1

I cannot verify my contract. I get these errors:
ParserError: Source "@openzeppelin/contracts/token/ERC20/ERC20.sol" not found: File import callback not supported
--> myc:4:1:
|
4 | import "@openzeppelin/contracts/token/ERC20/ERC20.sol"
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

ParserError: Source "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol" not found: File import callback not supported
--> myc:5:1:
|
5 | import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Burnable.sol"
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

ParserError: Source "@openzeppelin/contracts/token/ERC20/extensions/ERC20Snapshot.sol" not found: File import callback not supported
--> myc:6:1:
|
6 | import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Snapshot.sol"
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

ParserError: Source "@openzeppelin/contracts/access/AccessControl.sol" not found: File import callback not supported
--> myc:7:1:
|
7 | import "@openzeppelin/contracts/access/AccessControl.sol"
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

ParserError: Source "@openzeppelin/contracts/security/Pausable.sol" not found: File import callback not supported
--> myc:8:1:
|
8 | import "@openzeppelin/contracts/security/Pausable.sol"
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

ParserError: Source "@openzeppelin/contracts/token/ERC20/extensions/draft-ERC20Permit.sol" not found: File import callback not supported
--> myc:9:1:
|
9 | import "@openzeppelin/contracts/token/ERC20/extensions/draft-ERC20Permit.sol"
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

ParserError: Source "@openzeppelin/contracts/token/ERC20/extensions/ERC20Votes.sol" not found: File import callback not supported
--> myc:10:1:
|
10 | import "@openzeppelin/contracts/token/ERC20/extensions/ERC20Votes.sol"
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

ParserError: Source "@openzeppelin/contracts/token/ERC20/extensions/ERC20FlashMint.sol" not found: File import callback not supported
--> myc:11:1:
|
11 | import "@openzeppelin/contracts/token/ERC20/extensions/ERC20FlashMint.sol"
| ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^

2

You can flatten the contract using remix

3

Reccomend downloading and using Visual Studio Code if you're not already. Create or copy the contract file folder to your hard drive. Open it in from inside visual studio code. Open a terminal. Make sure you are in your project directory. In code, cd into your project direcrory, the top level to your contracts folder. Then install open zeppelin contracts using> npm install @openzepplin/contracts

4

If i flatten the contract, not compiling.

Warning: SPDX license identifier not provided in source file. Before publishing, consider adding a comment containing "SPDX-License-Identifier: " to each source file. Use "SPDX-License-Identifier: UNLICENSED" for non-open-source code. Please see https://spdx.org for more information.
--> contract_flattened.sol

5

"npm command not found"

6

Yes it is a remix bug. Simply add the spdx identkifier manually

7

how to do it? Im new to smart contracts

8

Please refer to our guide on verification:

If you want hands-on help please post in Developer Wanted.