The NHS website for booking Covid-19 vaccine appointments appeared to temporarily crash after people aged over 45 were offered jabs.
Some visitors to the site on Tuesday morning were faced with the message: “The NHS website is currently experiencing technical difficulties.
“We are working to resolve these issues. Thank you for your patience.”
Other users reported being placed in a queue, with a holding screen which read: “You are in a queue. Lots of people trying to book an appointment.”
Shortly after the vaccine booking site was hit by the technical issues, vaccines minister Nadhim Zahawi tweeted that the problem had been “fixed”.
It is understood that NHS Digital were able to get the website back up and running on Tuesday morning, with all issues being resolved and people able to book appointments.
One 47-year-old user from Bromley, south-east London, who only gave his name as Dean, encountered a problem as he tried to book a jab appointment at around 9.30am.
He said: “I seemingly booked, but the website crashed at the point of confirming contact details, ie giving phone number and email.
“Now, when I use my NHS number to check if my appointments exist, it will not let me find out without reference numbers for the (vaccine) bookings.
“But the paradox is, you need this from an email or text they would have sent.”
Dean was able to get back on to the website after it crashed for him, explaining: “It seemed to let me get to the point of checking my booking – but obviously this is impossible without a confirmation email/text.”
He has since tweeted at the official @NHSuk account, “hoping someone sees” to help him with the issue.
“I’ve already had at least four others say they have same problem,” Dean claimed, adding: “The problem is, that I may miss out on (the) vaccine because of this IT error. And I have no way of getting help or correcting it.”
Dean said that he may turn up at the vaccination centre and “hope for the best”.
The technical issues came as the NHS online booking system opened up to allow people over the age of 45 to arrange for their coronavirus vaccine as part of the start of “Phase 2” of the vaccination programme.
The NHS has previously been focused on ensuring vaccines are offered to those considered to most vulnerable to coronavirus – those aged over 50, people deemed be “clinically extremely vulnerable” and health and social care workers.
There are an estimated 3.7 million people in England aged 45 to 49.
According to the Government, in total almost 40 million doses of the Pfizer and AstraZeneca vaccines have been delivered since their rollout began in the UK in December, including 32 million first jabs and more than seven million second doses.