A number of bitcoin websites experienced downtime today over a period of roughly four hours due to what appears to be a DNS server error at a major Internet service provider (ISP).

Affected websites included local Latin American exchanges such as BlinkTrade, BitInka and SurBTC, as well as larger international startups such as Bitstamp, Blockchain, BTC-e and Coinbase.

Other outlets such as Bitcoin.org and LocalBitcoins remained accessible during this time, and at press time, all websites said to have been affected were once again online. However, a video provided to CoinDesk by local bitcoin users illustrated how pages suffered from long load times, eventually proving inaccessible.

Members of the local Venezuelan bitcoin community first began reporting the outages earlier today on Bitcoin Venezuela, a local Facebook group with more than 6,000 members.

An analysis by CoinDesk indicated the error was most likely due to an ISP issue, but that an error at distributed DNS services provider CloudFlare could have also caused the issue. Local reports connected the issue to a DNS server of state-owned ISP CANTV.

An examination of traceroute information provided by local users indicated the websites were not being blocked.

At the time, group admins indicated that the websites were reachable via broadband and DSL connections, and that mobile ISPs such as Digitel, Movistar and Movilnet were allowing access to pages, factors that pointed to CANTV as the source of the issue.

Due to CANTV's affiliation with the country's government, the outage stoked concerns that the websites were being purposefully blocked.

Similar incidents have already occurred this year in Russia, where the state's media watchdog group restricted access to five sites. Representatives of affected businesses later brought their case to court in April, at which time a judge restored access to the websites.

Founded in 1930 as a telephone service provider, CANTV was privatized in the early 1990s, but was taken over by the Venezuelan government in 2007 when the Hugo Chavez administration acquired a controlling stake in the publicly traded firm.

At press time, CANTV did not respond to requests for further information on the developments.

Website error image via Shutterstock