How to activate asterisk server and connect Zoiper to asterisk server? (FreePBX business app)

Hello, I need your help. As I was trying to make my own voip system using freepbx digitalocean business app, I had a problem. Here is what I’ve tried on it.

curl -v -u username:password http://server_ip:8088/ari/endpoints

Here is the result (logs):

*   Trying server_ip:8088...
* Connected to server_ip (server_ip) port 8088 (#0)
* Server auth using Basic with user 'username'
> GET /ari/endpoints HTTP/1.1
> Host: server_ip:8088
> Authorization: "token here"
> User-Agent: curl/7.81.0
> Accept: */*
> 
* Mark bundle as not supporting multiuse
< HTTP/1.1 200 OK
< Server: Asterisk/18.6.0
< Date: Thu, 04 Jan 2024 13:48:33 GMT
< Cache-Control: no-cache, no-store
< Content-type: application/json
< Content-Length: 113
< 
[
  {
    "technology": "PJSIP",
    "resource": "anonymous",
    "state": "offline",
    "channel_ids": []
  }
* Connection #0 to host server_ip left intact

sudo systemctl start asterisk

Here is the error log:

Asterisk is already running.
Can't open PID file /var/run/asterisk/asterisk.pid (yet?) after start: No such file or directory
Failed to start LSB: Asterisk PBX.

Unit asterisk.service entered failed state.
asterisk.service failed.
pam_unix(sudo:session): session closed for user root

How can I fix those issues? Hope to hear from you soon. Thank you.