Twitter's direct messaging feature appears to be experiencing technical difficulties by not allowing certain messages to be sent if they contain links.
The issue was first noticed by some users Wednesday night, with tweets flagging the issue continuing to appear through Thursday morning and into the early afternoon.
Apparently, whether a message can successfully be sent depends on the link it contains. In internal tests, messages containing links to Twitter.com, Facebook.com, YouTube.com and NYTimes.com appeared to work fine. But messages containing links to Google.com did not go through, and neither did messages containing links to Businesswire.com, Inquisitr.com, PCWorld.com or Computerworld.com.
Twitter could not immediately be reached to comment on the issue, though in other reports the company described the problem as a "technical issue with URLs."
Some users' problems, however, suggest there might be more going on. When trying to send a message containing a link, some users reported seeing a message that read, "Permission denied. There was an error sending your message: Text contains malware."
Tweets and direct messages containing links can be dangerous on Twitter, and in the past have been used to hijack members' accounts. In the Netherlands, users reported earlier this year that they were targeted by malicious malware. In that case, hackers used links within Twitter to land people on external sites that would attack their browser and deliver malware.
Twitter already tries to flag certain URLs to prevent phishing and scams, by blocking the posting of suspected malware URLs and flagging suspected harmful shortened URLs. Harmful sites may include phishing sites, sites that download malicious software to the user's computer, or spam sites that request personal information, the company says.
Better policing the links users send through direct messages, therefore, would make sense for Twitter.
Twitter's direct messaging feature has lately been undergoing some experimentation. Last week a new account appeared on Twitter called "Event Parrot," which uses direct messages to keep users up-to-date on the news. On Thursday, direct messages were still sent through that service, with functioning links to sites like NBC News.