Users of cryptocurrency exchange Poloniex were making complaints about account “freezes” May 27 after completing mandatory new identity verification procedures.

Account holders on social media claim that after confirming their identity, they receive notification that they may now continue trading, but their previously-functional account is now blocked.

The problems, which Poloniex has not appeared to specifically acknowledge, began the same day the exchange issued notice to users demanding they link their identitity with their account.

“We are asking all legacy Poloniex customers who have not provided full identification information in the past to do so now through the Poloniex profile page,” the notice reads.

“This page provides clear instructions on what information is required to verify your account. As soon as you submit this information, we will take steps to verify it and re-enable trading and transactions for your account.”

Some of you have raised questions about recent updates to our onboarding and identity verification processes. Rest assured your funds are safe, and please see our product update with more detail on next steps: https://t.co/2LgDv0g17m — Poloniex Exchange (@Poloniex) May 27, 2018

The move echoes similar requirements now in place at fellow exchange Bitfinex and less stringent measures on p2p marketplace Localbitcoins.

Frozen accounts appear to affect many users going through verification, with multiple reports confirming the problem persists.

In February, Poloniex was sold to Goldman Sachs-backed Circle in a $400 mln deal. As of press time, it is the 25th largest exchange in the world by trade volume, according to Coinmarketcap data.