Users of Microsoft's instant-messaging service found themselves unable to share links to YouTube videos on Friday evening and Saturday morning, sparking brief worries of a possible Microsoft-led effort to block access to the Google-owned video-sharing site.
Microsoft said in a blog posting Sunday that the issue was a mistake made by the third party that handles blocking of potentially unsafe content for MSN Messenger and Windows Live Messenger.
"As some of you noticed, we had a problem from Friday night to Saturday morning where our Messenger service was incorrectly blocking some legitimate IP addresses," a Microsoft employee said on the company's Messenger blog. "We sincerely apologize for any difficulties this caused our users."
The company thanked users to alerting it to the problem. "Because of your help, the incorrect block was only in place for a few hours."
Microsoft also tried to throw cold water on some of the "outlandish speculation" on the cause of the problem.
"Microsoft did not request to block any of the URLs that were accidentally blocked," it said in the blog. "The blocks were made by our partner as a result of their process to block harmful URLs. We are still investigating the specific reason our partner made these incorrect blocks and we will work with them to improve their process for detecting harmful URLs while not blocking safe ones."