libserialport returned SP_ERR_FAIL

I am trying to plot serial port real-time data (pico and ads1115) with the following julia script:

using Plots, DataStructures, LibSerialPort
using Plots:px

# plotting setting
plot_font = "Arial";

default(fontfamily=plot_font,
        linewidth=3, framestyle=:grid,# ":box" ":semi" ":origin" ":zerolines" ":grid" ":none"
        grid=true,
        titlefontsize=24,
        guidefontsize=30, # means labelfontsize
        tickfontsize=28,
        legendfontsize=18,
        legend=:outertopright,
        fg_legend = :false);

function print_serial_data(port_name, baudrate, buffer_size)

    # Create a circular buffer to store data
    data_buffer = CircularBuffer{Float64}(buffer_size)
    time_data = CircularBuffer{Float64}(buffer_size)

    start_time = time();

    # Open the serial port, Real-time plotting loop
    while true
        LibSerialPort.open(port_name, baudrate) do sp
            # Read a line of data from the serial port
            line = readline(sp)

            if line in ["", ".", "-"]
                volt_data = 0.0;
            else
                volt_data = parse(Float64, line)
            end

            # Calculate elapsed time in seconds
            elapsed_time = time() - start_time  

            # Append data to the buffers
            push!(data_buffer, volt_data)
            push!(time_data, elapsed_time)

            # Update the plot
            volt_vec = convert(Vector{Float64}, data_buffer);
            time_vec = convert(Vector{Float64}, time_data);

            p = plot(time_vec, volt_vec)

            plot!(title = "",
            size=(950,500),
            left_margin = 40px,
            right_margin = 70px,
            bottom_margin = 70px,
            xlabel="Time (s)",
            ylabel="Voltage (V)",
            tickfontsize=18,
            guidefontsize=22,
            legend = :none,
            framestyle = :box,
            dpi = 500,
            )

            display(p)

            sleep(0.004) # unit second
        end
    end
end

print_serial_data("/dev/ttyACM0", 115200, 200)

My device is "/dev/ttyACM0", and it works well with only line printing (no plotting). But when I add a plotting function inside the LibSerialPort.open(port_name, baudrate) do sp. I encounter the issue:

OS error code 16: Device or resource busy ERROR: LoadError: libserialport returned SP_ERR_FAIL - Host OS reported a failure. Stacktrace: [1] error(s::String) @ Base ./error.jl:35 [2] check(ret::LibSerialPort.Lib.SPReturn) @ LibSerialPort.Lib ~/.julia/packages/LibSerialPort/i1kHh/src/wrap.jl:299 [3] sp_open(port::Ptr{LibSerialPort.Lib.SPPort}, mode::SPMode) @ LibSerialPort.Lib ~/.julia/packages/LibSerialPort/i1kHh/src/wrap.jl:341 [4] open(portname::String, baudrate::Int64; mode::SPMode, ndatabits::Int64, parity::SPParity, nstopbits::Int64) @ LibSerialPort ~/.julia/packages/LibSerialPort/i1kHh/src/LibSerialPort.jl:474 [5] open(portname::String, baudrate::Int64) @ LibSerialPort ~/.julia/packages/LibSerialPort/i1kHh/src/LibSerialPort.jl:467 [6] open(::var"#1#2"{Float64, CircularBuffer{Float64}, CircularBuffer{Float64}}, ::String, ::Vararg{Any}; kwargs::@Kwargs{}) @ Base ./io.jl:394 [7] open @ ./io.jl:393 [inlined] [8] print_serial_data(port_name::String, baudrate::Int64, buffer_size::Int64) @ Main ~/pico/pico-ads1115/getads/serial_plot/julia/libserial-plot.jl:30 [9] top-level scope @ ~/pico/pico-ads1115/getads/serial_plot/julia/libserial-plot.jl:75 in expression starting at /home/tim/pico/pico-ads1115/getads/serial_plot/julia/libserial-plot.jl:75

I am using Ubuntu 22LTS. How to fix the problem? Thanks in advance.

JuliaIO / LibSerialPort.jl

libserialport returned SP_ERR_FAIL #98