Boots has said it is no longer taking bookings for the flu shot "due to unprecedented demand".
Officials have warned influenza as well COVID-19 could be floating around at the same time prompting people eligible for vaccination.
People who are given priority for the NHS stab include those over 65, those with underlying health conditions like lung disease or diabetes, and pregnant women.
The Department of Health and Welfare also recommends that children aged 2-11 and anyone who provides primary care for an elderly or disabled person, or who lives in a house with a screen, receive it.
This year, for the first time, the flu vaccine will be offered to people over 50 in England, Wales and Northern Ireland and to people over 55 in Scotland.
It's also available as a paid service at pharmacies such as Boots.
However there Coronavirus Cases are rising, keeping up with demand seems to have become a problem.
A statement posted on Boots' website said: "Due to the unprecedented demand for flu vaccinations this year and the availability of inventory, we have had to suspend bookings."
NHS England has said stocks of live vaccines are available as experts warn that people should "not be complacent" about flu.
Health Secretary Matt Hancock told Kay Burley that there are "more than enough" supplies of vaccines and that we have "record" amounts.
Shadow Chancellor Anneliese Dodds told Sky News that she had heard from voters in Oxford that they were having trouble accessing the push.
She said it is important that the logistics be sorted to prevent this from becoming a major problem.
He said there are 30 million cans and the fact that there is a lot of demand is a "very good thing".
Those infected with both the flu and COVID-19 are at a seriously increased risk of death, according to Public Health England (PHE).
The flu vaccination program has expanded this year to include more people than ever before – up to 30 million people in England.
The campaign was launched because a new study showed that people infected with both the new coronavirus and the flu were six times more likely to die than the general population during the first peak of the pandemic.
The risk of death was also higher than if infected with COVID-19 alone.
Like the coronavirus, the flu is spread through coughing and sneezing. It is therefore important that those affected stay at home and have some distance from others.
If you think you have the flu or coronavirus, isolate yourself and anyone with health problems or over the age of 65 should call NHS 111.