Before connecting Venly wallet at Opensea you need to import the Matic wallet into an Ethereum wallet, that are the only ones you can connect to Opensea.
Sign it with your PIN and confirm. Your new ETH wallet should have the same name of your Matic one.
If you already connected to Opensea the ETH wallet not imported from Matic, go to the page of that wallet in Venly and unlink it from Opensea. Then login again to Opensea and choose the ETH wallet imported from Matic.
(NFTs will remain in the Matic wallet and on the Polygon network)
If it doesn't work, contact our support via chat!
- MAUER Team