Make sure that you are on claim-erc20.omniatech.io in your browser tab. This claim portal will never ask you to approve token to any address.
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Omnia Token Claiming Portal

Make sure you are using the official claim portal - you can double check by going to website omniatech.io and cross-check links in footer.

Use this portal to claim ERC20 OMNIA tokens on Ethereum Mainnet. If you have been informed that your vesting is on Binance Smart Chain Mainnet you need to use BEP20 OMNIA tokens claim portal.

Connect your wallet to see if you are eligible for OMNIA token claim