While the cryptocurrency Bitcoin has soared to new highs again Thursday, breaking the $15,000 and $16,000 barriers , popular digital asset broker Coinbase has come under fire for experiencing downtime and overcharging traders.

Coinbase, which may be the most popular platform for buying and selling Bitcoin, has become notorious for its unannounced downtime that makes the site inaccessible. It suffered from one of those outages Thursday while the price of Bitcoin was rising, with many visitors receiving an "Error 502" message.

According to the company’s website , which tracks issues and downtime, Coinbase started experiencing high traffic around 11:00 a.m. ET, which resulted in customers experiencing slow performance on the site or issues logging into their Coinbase account.

Additionally, Coinbase reported experiencing issues with its identification verification system—a tool that is used to authenticate new users, who are required to show a form of identification when setting up an account. At around 1:00 p.m. ET, Coinbase reported that the ID system was failing to complete “for a significant number of customers” because of high traffic.

The issues have caused what the site calls “degraded performance” for cryptocurrency traders, making it difficult to buy and sell Bitcoin right as the currency was reaching new heights.

For those who were able to trade during the period of performance issues, Coinbase may have overcharged. According to Peter Brandt , a commodities traders, users who bought Bitcoin through Coinbase may have paid more than $2,000 more than what the actual price for the currency was.

“If you bought [Bitcoin] a few minutes ago [on Coinbase] you over paid by more than $2,000 per,” Brandt wrote on Twitter. “But of course it is worth it since its web site is usually down and you cannot reach tech support.”

Brandt documented the list price to buy Bitcoin from Coinbase as $18,238.30 while the actual value of the cryptocurrency at the time was $16,000. Bitcoin has yet to crack the $17,000 barrier, let alone the price Coinbase charged users to buy the cryptocurrency.

International Business Times reached out to Coinbase regarding the price difference but did not receive a response at the time of publication.

Coinbase’s issues come right as Bitcoin broke new thresholds Thursday. The cryptocurrency continued its rocketing rise, reaching the $15,000 and $16,000 milestone during the course of the day. The rise caps a 48 hour period in which the cryptocurrency experienced more than 25 percent growth.

The rise for Bitcoin over the course of 2017 has been exponential. The cryptocurrency started the year valued at below $1,000. By September, it was valued at around $3,250 and has risen rapidly in the months that have followed.

Opinions on how long the rise will last vary. George Tung, the owner of CryptosRus.com , wrote in an op-ed for International Business Times that he expects Bitcoin will continue its rise next year. “I see 2018 being just as good — if not better,” he said. Others, like venture capitalist Lou Kerner, thinks Bitcoin’s bubble is due to bust and could be “one of the greatest shorting opportunities ever.”