(NEXSTAR) – When the White House launched its plan to send Americans free at-home COVID-19 tests, many logged on to the USPS site to place their orders immediately. Anyone who tried to come back for more quickly hit a wall: “At-home COVID-19 tests have already been ordered for this address.”

That’s because there’s a strict limit of one (1) order per residential address. Each order contains four COVID-19 tests.

At this time, there are no exceptions to the four-test limit. Even if you live in a household with more than four people, multiple generations, lots of roommates or any similar setup, you’re still limited to four tests.

The White House offers an explanation on its website: “To promote broad access, the initial program will only allow 4 free individual tests per residential address.” (Note the statement mentions “initial program” — no word on the next phase or what the limit might look like going forward.)

Some people living in duplexes, apartments, co-ops, or other housing setups outside single-family homes complained Tuesday that the site wouldn’t let them order tests even though no one else in their household had claimed their allotment. If you’re running into that problem, there’s a chance you may be filling out the fields wrong.

If you run up against the four-test limit and need more kits, you’re also still eligible to get up to eight at-home tests, per month per person, reimbursed by your private insurance. (Medicare recipients are not eligible.) That means a family of six could get up to 48 at-home COVID tests covered per month.

Health and Human Services also has a site set up to help you find free COVID-19 testing sites in your area.