If you created your wallet through XDC web wallet website using Mnemonic/seed phrase and password combination then you won't be able to import the same wallet to Metamask using Mnemonic phrase only.
Instead log into your wallet using MEW (My Ether Wallet) using same credentials and Once you are able to access your wallet dashboard, click on portfolio value tab and then paper wallet tab to see and download your private key backup. With that private key you can import that account to Metamask/Rabby or any supported wallet.
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If you created your wallet through XDC web wallet website using Mnemonic/seed phrase and password combination then you won't be able to import the same wallet to Metamask using Mnemonic phrase only.
Instead log into your wallet using MEW (My Ether Wallet) using same credentials and Once you are able to access your wallet dashboard, click on portfolio value tab and then paper wallet tab to see and download your private key backup. With that private key you can import that account to Metamask/Rabby or any supported wallet.