fluentd is not sending logs to mongodb

[Noobie-hacker]

I am new to fluntd. I am trying to send apache logs to mongodb server using fluentd. everything seems working properly but logs are not getting inserted in mongdb.
here is the td-agent.conf configuraration:

<source>
  @type tail
  path /var/log/apache2/access.log
  pos_file /var/log/td-agent/apache2/access.log.pos
  tag mongo.apache.access
  <parse>
    @type json
    keep_time_key true
  </parse>
</source>
# Single MongoDB
<match mongo.**>
  @type mongo
  connection_string mongodb://<username>:<pass>@<mongodb_ip>:1416/
  host 52.66.238.231
  port 1416
  database fluentd
  collection test
  <inject>
    # key name of timestamp
    time_key time
  </inject>
  <buffer>
    # flush
    flush_interval 1s
  </buffer>
</match>

here is the td-agent.log:

</buffer>
 </match>
</ROOT>
2023-09-12 04:55:14 +0000 [info]: starting fluentd-1.16.2 pid=683937 ruby="3.1.4"
2023-09-12 04:55:14 +0000 [info]: spawn command to main:  cmdline=["/opt/td-agent/bin/ruby", "-Eascii-8bit:ascii-8bit", "/opt/td-agent/bin/fluentd", "--log", "/var/log/td-agent/td-agent.log", "--daemon", "/var/run/td-agent/td-agent.pid", "--under-supervisor"]
2023-09-12 04:55:15 +0000 [info]: #0 init worker0 logger path="/var/log/td-agent/td-agent.log" rotate_age=nil rotate_size=nil
2023-09-12 04:55:15 +0000 [info]: adding match pattern="mongo.**" type="mongo"
2023-09-12 04:55:15 +0000 [info]: adding source type="tail"
2023-09-12 04:55:15 +0000 [info]: #0 starting fluentd worker pid=683947 ppid=683944 worker=0
2023-09-12 04:55:15 +0000 [info]: #0 fluentd worker is now running worker=0

kindly let me know what i am doing wrong. Thanks in advance.