No sound on laptop ubuntu 20.04

I have no sound on my laptop (Ubuntu 20.04), there is no problem with alphamixer.

I tried to reinstall pulseaudio and alsa-base several times with no success.

I also tried to delete ~/.config/pulse/ and then reboot my laptop, still no success.

The output of pulseaudio is

E: [pulseaudio] pid.c: Daemon already running.
E: [pulseaudio] main.c: pa_pid_file_create() failed.

The output of pulseaudio -vvvv is

I: [pulseaudio] main.c: setrlimit(RLIMIT_NICE, (31, 31)) failed: Operation not permitted
I: [pulseaudio] main.c: setrlimit(RLIMIT_RTPRIO, (9, 9)) failed: Operation not permitted
D: [pulseaudio] core-rtclock.c: Timer slack is set to 50 us.
D: [pulseaudio] core-util.c: RealtimeKit worked.
I: [pulseaudio] core-util.c: Successfully gained nice level -11.
I: [pulseaudio] main.c: This is PulseAudio 13.99.1
D: [pulseaudio] main.c: Compilation host: x86_64-pc-linux-gnu
D: [pulseaudio] main.c: Compilation CFLAGS: -g -O2 -fdebug-prefix-map=/build/pulseaudio-IJhHIk/pulseaudio-13.99.1=. -fstack-protector-strong -Wformat -Werror=format-security -Wall -W -Wextra -pipe -Wno-long-long -Wno-overlength-strings -Wunsafe-loop-optimizations -Wundef -Wformat=2 -Wlogical-op -Wsign-compare -Wformat-security -Wmissing-include-dirs -Wformat-nonliteral -Wpointer-arith -Winit-self -Wdeclaration-after-statement -Wfloat-equal -Wmissing-prototypes -Wredundant-decls -Wmissing-declarations -Wmissing-noreturn -Wshadow -Wendif-labels -Wcast-align -Wstrict-aliasing -Wwrite-strings -Wno-unused-parameter -fno-common -fdiagnostics-show-option -fdiagnostics-color=auto
D: [pulseaudio] main.c: Running on host: Linux x86_64 5.4.0-53-generic #59-Ubuntu SMP Wed Oct 21 09:38:44 UTC 2020
D: [pulseaudio] main.c: Found 4 CPUs.
I: [pulseaudio] main.c: Page size is 4096 bytes
D: [pulseaudio] main.c: Compiled with Valgrind support: no
D: [pulseaudio] main.c: Running in valgrind mode: no
D: [pulseaudio] main.c: Running in VM: no
D: [pulseaudio] main.c: Running from build tree: no
D: [pulseaudio] main.c: Optimized build: yes
D: [pulseaudio] main.c: FASTPATH defined, only fast path asserts disabled.
I: [pulseaudio] main.c: Machine ID is 9a5549b474a04f07a177feb358f508b6.
I: [pulseaudio] main.c: Using runtime directory /run/user/1000/pulse.
I: [pulseaudio] main.c: Using state directory /home/pnsuau/.config/pulse.
I: [pulseaudio] main.c: Using modules directory /usr/lib/pulse-13.99.1/modules.
I: [pulseaudio] main.c: Running in system mode: no
E: [pulseaudio] pid.c: Daemon already running.
E: [pulseaudio] main.c: pa_pid_file_create() failed.

What can I do to solve my problem?