An exchange usually blocks a deposit when its compliance system flags sanctions, mixer or stolen-fund exposure in the sending wallet's history; Plastron lets you identify that exposure free before you deposit.

When a cryptocurrency exchange blocks a deposit or freezes an account, most users have no immediate idea why it happened. Exchanges are legally prohibited from disclosing the specific details of an AML investigation — the same confidentiality rules that govern bank suspicious activity reports apply to exchange compliance actions. What users typically receive is a generic notification asking for source-of-funds documentation, with no indication of which transaction or counterparty triggered the review. This information asymmetry puts users at a significant disadvantage. Without knowing what the exchange flagged, it is nearly impossible to prepare an effective response. You might spend days gathering documentation for an irrelevant transaction while the actual flag — a single interaction with a mixer-linked address three months ago — goes unaddressed. The most common triggers for exchange deposit freezes are OFAC sanctions exposure (direct or indirect), mixer involvement (especially Tornado Cash interactions after August 2022), receipt of funds that trace back to known hacks or exploits, and wallets with high darknet or fraud exposure. Less commonly, an exchange may flag a wallet solely based on its counterparty graph — if a large proportion of your transaction counterparties are unidentified or have unknown entity types, some exchanges treat that as elevated risk. Running a Plastron scan immediately after a deposit is blocked gives you a map of your wallet's risk profile from the outside — the same perspective the exchange compliance team is reviewing.