OpenSea, the biggest non-fungible token (NFT) Marketplace has suffered a significant breach of information after a good portion of their client’s emails was leaked by their bulk email service provider.

According to official information, the leak occurred after an employee of Customer.io had misused their access to the provider’s clients’ data. OpenSea has advised its users to beware of spam and phishing attacks, saying:

“Because the data compromise included email addresses, there may be a heightened likelihood for email phishing attempts. Please be aware that malicious actors may try to contact you using an email address that looks visually similar to our official email domain, ‘opensea.io’ (such as ‘opensea.org’ or some other variation).”

The platform has announced that an official investigation into the matter has begun. It is, however, not the first of such investigations, following the data breach of OpenSea’s Discord channel earlier this year.

Incidents such as these underline the ever-increasing importance of online and data security across cyberspace. Several OpenSea users have already taken to Twitter to complain about an overflow of spam emails, and it is clear that such complaints are going to continue.