The Federal Communications Commission’s Web comments form crashed Tuesday morning in the hours before the agency’s first deadline for submitting comments on its net neutrality proposal. So the FCC is extending that deadline.

The FCC’s Electronic Comment Filing System (ECFS) was generating an error message at 10:15 a.m. EST Tuesday, the last day for first-round comments on the agency’s proposed net neutrality rules. The deadline for first-round comments had been 11:59 p.m. Tuesday, with a 60-day round for replies to the original comments to follow.

The FCC, on Tuesday afternoon, extended the first-round deadline to file comments until Friday, due to problems with the ECFS.

“Not surprisingly, we have seen an overwhelming surge in traffic on our website that is making it difficult for many people to file comments,” FCC Press Secretary Kim Hart said by email. “Please be assured that the commission is aware of these issues and is committed to making sure that everyone trying to submit comments will have their views entered into the record.”

While the ECFS Web form was down Tuesday morning, the FCC also has an email address, at openinternet@fcc.gov, for people to submit comments. Between the Web form and the email address, the agency had received 677,000 comments on net neutrality as of Monday afternoon, making it one of the most commented proceedings in FCC history. (An FCC spokesperson told the Washington Post that the figure had grown to 780,000 by Tuesday afternoon.)

The proposed net neutrality rules haven’t set a comment record, however, with partial nudity still trumping Internet openness. The FCC received about 1.4 million comments related to singer Janet Jackson’s so-called “wardrobe malfunction” on live television during the 2004 Super Bowl, Hart said.

Many of the people submitting comments called on the FCC to regulate broadband providers as common-carrier utilities as a way to enforce strong rules against selectively blocking or slowing Web traffic. On Tuesday morning, a group of four senators, three Democrats and an Independent, hosted a press conference calling on the FCC to pass strong net neutrality rules.

At the press conference, Democratic Senators Ed Markey of Massachusetts, Al Franken of Minnesota, and Charles Schumer of New York, along with Bernie Sanders, a Vermont independent, called on the FCC to reclassify broadband as a regulated utility. “We need to put on the books the strongest open Internet rules possible,” Markey said in a video.

In April, FCC Chairman Tom Wheeler proposed new rules in response to a decision months earlier by the U.S. Court of Appeals for the District of Columbia Circuit to strike down the agency’s 2010 net neutrality rules. But many critics have protested Wheeler’s proposal, which would allow broadband providers to engage in “commercially reasonable” traffic management, as too weak to protect Web-based video and other services from interference by broadband providers.

Net neutrality advocates have also criticized Wheeler for declining so far to prohibit broadband providers from charging Web services for paid priority traffic handling in limited cases.

Many net neutrality advocates have called on the FCC to regulate broadband providers like traditional telecom providers, under common-carrier rules in Title II of the Telecommunications Act. Wheeler has said that Title II reclassification remains on the table at the FCC.

Other telecom experts called on the FCC to take smaller steps. Paid prioritization and similar traffic management techniques are useful tools for some Internet apps, said Richard Bennett, visiting fellow at free-market think tank the American Enterprise Institute’s Center for Internet, Communications, and Technology Policy. Prioritization allows voice calls to work on Wi-Fi and LTE mobile networks, he wrote in comments to the FCC.

“It’s fashionable in net neutrality circles to castigate something called ‘paid prioritization’ by its critics as contrary to various historical norms of Internet practice, yet there is no doubt ... that prioritization systems and their close relatives, bandwidth reservation systems, are often extremely helpful,” Bennett wrote. “It should be clear that a ban on prioritization and other means of achieving low-latency quality of service is effectively a ban on VoIP over the open public Internet.”

Updated at 2:57 p.m. PT to note the new deadline for comments.