Coinbase, Binance, Kraken, and Gemini—four of the world's most prominent cryptocurrencycryptocurrency exchanges—experienced technical issues on Thursday after the price of Bitcoin shot past $40,000.

Coinbase appears to be the hardest hit; the site's page on isitdownrightnow.com is currently flooded with comments from users who say they can't access the service.

A tweet from the company's support account says they're aware of the issue, and are actively working on a fix.

Changpeng Zhao, CEO of Binance, wrote that "Bitcoin ATH [all-time high] comes with ATH loads," and said the exchanges "is experiencing a small websocket issue."

No word yet on whether Binance has made any progress.

Kraken, which has been reckoning with load issues for the past few hours, said on a designated support page that those issues are solved, for now. Earlier today, the company was forced to limit certain kinds of transactions.

A Gemini support page says that the company's systems are "currently experiencing degraded performance," and that they're "continuing to investigate this issue," though there have been no further updates on the site.

A spokesperson for Gemini told Decrypt that the exchange "experienced no downtime or outages today although there have been brief periods where users may have experienced some site slowness during high peak periods." The spokesperson added that Gemini has added additional capacity to deal with the surge in demand and "will continue to do so as needed."

Spokespeople at Coinbase, Binance and Kraken were not immediately available for comment.

Editor's note: This story was updated after publication to include comments from Gemini.