The British government has offered to work with the electoral commission to extend the deadline ahead of the referendum. But as UK citizens prepare for the historic vote, Europeans have cast doubt on the EU.
The UK Electoral Commission on Wednesday urged the government to introduce legislation necessary to extend the deadline for registering to vote in a referendum on the UK's future in the EU.
The registration website crashed shortly before midnight Tuesday, preventing would-be voters from registering to cast their vote in referendum.
"It is vital that everyone who wants to participate in this historic referendum is able to," said the Electoral Commission in a statement.
"There will be many people who wanted to register to vote last night and were not able to," the commission added.
Labour Party leader Jeremy Corbyn demanded that the deadline for registration be extended.
Prime Minister David Cameron's office issued a statement saying: "We're working with the Electoral Commission to ensure those who register today and those registered last night will be able to vote."
The commission registered more than 500,000 applications on Tuesday before the website crashed, bringing the total number to 2,178,000 since it launched a "public awareness campaign."
EU losing support?
Less than a month ahead of the June 23 vote, a survey by the Pew Research Center suggested that 48 percent of British voters had an unfavorable opinion of the 28-nation bloc, compared to 44 percent who were in favor.
It also showed dwindling support across the bloc, with "a median of just 51 percent" across 10 EU countries surveyed showing a favorable view to the bloc.
Greece ranked the highest among disapproving nations, with 71 percent of respondents expressing "unfavorable" views of the EU. France ranked second with 61 percent.