It's not just you — the internet was super slow this morning.

Twitter, Spotify, Pinterest, Imgur, Etsy and Reddit were among the dozens of websites experiencing issues loading on Friday, Gizmodo reported. The culprit was likely a Distributed Denial of Service attack, also called a DDOS attack, on Dyn, a prominent internet performance management company that helps websites register their domain names and host their pages.

The service problems began just after 7 a.m. EDT. At that time, Dyn wrote that it "began monitoring and mitigating a DDoS attack against our Dyn Managed DNS infrastructure," using the acronym for Denial of Service. It caused "increased DNS query latency and delayed zone propagation." Essentially, the function that loads URLs like ibtimes.com went down due to hackers, Bloomberg reported.

The east coast of the United States was most affected. Other sites with outages included CNN, GitHub, SoundCloud and the Guardian, according to YCombinator.

Dyn quickly directed its engineers to fix the issue, then wrote on its website that services were back to normal as of 9:20 a.m. EDT. But the complaints (and jokes) on social media continued:

While for some people the outages were nothing but an annoyance, for others they posed a serious problem. Many sites likely lost revenue, according to the Daily Dot, while at least one expert warned that Friday's attack could point to a larger issue.

"DNS has often been neglected in terms of its security and availability from an enterprise perspective," Richard Meeus, of the internet security firm NSFOCUS, told the Inquirer. "This attack highlights how critical DNS is to maintaining a stable and secure internet presence, and that the DDoS mitigation processes businesses have in place are just as relevant to their DNS service as it is to the web servers and data centers."

It wasn't immediately clear who was behind the attack.