Dropdown Menu Error: React.Children.only expected to receive a single React element child

[MarkForLoop]

I am trying to use the dropdown as seen here (https://ui.shadcn.com/docs/components/dropdown-menu)

i am trying to use the sub dropdown part in the example but with when i am trying to do it i am getting this error

Unhandled Runtime Error Error: React.Children.only expected to receive a single React element child.

          <DropdownMenu>
            <DropdownMenuTrigger asChild>
              <button className="flex items-center justify-center gap-1 rounded border-[0.5px] border-newBrand-darkOrange bg-newBrand-orange px-2 py-1">
                <DownloadIcon className="h-6 w-6 stroke-white" />
                <span className="text-base font-light text-white">
                  Export Data
                </span>
                <ChevronDownIcon className="h-6 w-6 stroke-white" />
              </button>
            </DropdownMenuTrigger>
            <DropdownMenuContent
              side="bottom"
              sideOffset={4}
              align="center"
              alignOffset={4}
              className="rounded border-[0.5px] border-newBrand-darkOrange p-0"
            >
              <DropdownMenuItem className="flex items-center justify-between rounded-none border-b-[0.5px] border-newBrand-darkOrange bg-newBrand-orange px-[13px] py-1 hover:bg-newBrand-orange">
                <span className="text-base font-light text-white">
                  Download
                </span>
                <ChevronRightIcon className="h-6 w-6 stroke-white" />
              </DropdownMenuItem>

              <DropdownMenuSub>
                <DropdownMenuSubTrigger asChild>
                  <button className="flex items-center justify-between rounded-none bg-newBrand-orange px-[13px] py-1">
                    <span className="text-base font-light text-white">
                      Email
                    </span>
                    <ChevronDownIcon className="h-6 w-6 stroke-white" />
                  </button>
                </DropdownMenuSubTrigger>

                <DropdownMenuPortal>
                  <DropdownMenuSubContent>
                    <DropdownMenuItem>PDF</DropdownMenuItem>
                    <DropdownMenuItem>CSV</DropdownMenuItem>
                  </DropdownMenuSubContent>
                </DropdownMenuPortal>
              </DropdownMenuSub>
            </DropdownMenuContent>
          </DropdownMenu>