The client does not work properly after installation

Hi all：
`uname -a` info is `Linux VM-111-46-ubuntu 4.15.0-54-generic #58-Ubuntu SMP Mon Jun 24 10:55:24 UTC 2019 x86_64 x86_64 x86_64 GNU/Linux`.
And I got grr by the command ` wget https://storage.googleapis.com/releases.grr-response.com/grr-server_3.3.0-8_amd64.deb`，so my grr version is 3.3.0.8
I install grr according to this page [Installing from a release server deb (recommended)](https://grr-doc.readthedocs.io/en/latest/installing-grr-server/from-release-deb.html), but I changed some steps.
1. I am using the MySQL instance provided by a Public Cloud, not the self-built MySQL on the same server
2. The value of max_allowed_packet is 1073741824, more than 20971520
3. I change the command from`CREATE USER 'grr'@'localhost' IDENTIFIED BY 'password';` to `CREATE USER 'grr'@'%' IDENTIFIED BY 'password';` ,and `GRANT ALL ON grr.* TO 'grr'@'%';`， because the grr user of the database should be able to log in remotely
**I used root of MySQL when I installing grr，because it recommended me to use**，I don't know if this is correct.
and now my problem is : The client sometimes does not work properly. Like the picture I attached.

1. It stuck at the stage of host information collection stage, and a lot of host information can not be collected，like “Memory Size”、“Users”、“MAC”....,
2. Folw created by GRRWorker is always "running" but no result

I found some "OperationalError: (2006, 'MySQL server has gone away')" in both grr-http-server.log and grr-worker.log , but Mysql is actually working properly.

**example of grr-worker.log:**
`ERROR:2019-11-16 05:29:54,143 21986 MainProcess 140281434961664 flow_processing_request_handler mysql_flows:1227] _FlowProcessingRequestHandlerLoop raised (2006, 'MySQL server has gone away').
Traceback (most recent call last):
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/databases/mysql_flows.py", line 1218, in _FlowProcessingRequestHandlerLoop
msgs = self._LeaseFlowProcessingReqests()
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/databases/db_utils.py", line 52, in Decorator
result = f(*args, **kwargs)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/databases/mysql_utils.py", line 245, in Decorated
return self._RunInTransaction(Closure, readonly)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/databases/mysql.py", line 576, in _RunInTransaction
connection.rollback()
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/databases/mysql_pool.py", line 136, in rollback
self.con.rollback()
OperationalError: (2006, 'MySQL server has gone away')`

**example of grr-http-server.log:**
`ERROR:2019-11-15 20:05:21,507 21991 MainProcess 140303775708928 Thread-7537 frontend:189] Had to respond with status 500.
Traceback (most recent call last):
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/bin/frontend.py", line 183, in do_POST
self.Control()
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_core/stats/stats_utils.py", line 53, in Decorated
return func(*args, **kwargs)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_core/stats/stats_utils.py", line 32, in Decorated
return func(*args, **kwargs)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/bin/frontend.py", line 247, in Control
request_comms, responses_comms)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_core/stats/stats_utils.py", line 53, in Decorated
return func(*args, **kwargs)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_core/stats/stats_utils.py", line 32, in Decorated
return func(*args, **kwargs)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/frontend_lib.py", line 239, in HandleMessageBundles
request_comms)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_core/lib/communicator.py", line 492, in DecodeMessages
remote_public_key = self._GetRemotePublicKey(source)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/frontend_lib.py", line 81, in _GetRemotePublicKey
md = data_store.REL_DB.ReadClientMetadata(remote_client_id)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/databases/db.py", line 676, in ReadClientMetadata
result = self.MultiReadClientMetadata([client_id])
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/databases/db.py", line 2829, in MultiReadClientMetadata
return self.delegate.MultiReadClientMetadata(client_ids)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/databases/db_utils.py", line 52, in Decorator
result = f(*args, **kwargs)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/databases/mysql_utils.py", line 245, in Decorated
return self._RunInTransaction(Closure, readonly)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/databases/mysql.py", line 576, in _RunInTransaction
connection.rollback()
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/databases/mysql_pool.py", line 136, in rollback
self.con.rollback()
`
and I find a lot of error log in grr-http-server.log like this.
`ERROR:2019-11-15 22:14:21,860 21991 MainProcess 140303307884288 Thread-16201 frontend:189] Had to respond with status 500.
Traceback (most recent call last):
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/bin/frontend.py", line 183, in do_POST
self.Control()
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_core/stats/stats_utils.py", line 53, in Decorated
return func(*args, **kwargs)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_core/stats/stats_utils.py", line 32, in Decorated
return func(*args, **kwargs)
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/bin/frontend.py", line 252, in Control
self.Send(responses_comms.SerializeToBytes())
File "/usr/share/grr-server/local/lib/python2.7/site-packages/grr_response_server/bin/frontend.py", line 94, in Send
self.wfile.write(header.encode("utf-8"))
File "/usr/lib/python2.7/socket.py", line 328, in write
self.flush()
File "/usr/lib/python2.7/socket.py", line 307, in flush
self._sock.sendall(view[write_offset:write_offset+buffer_size])
error: [Errno 104] Connection reset by peer
`
Thank you very much!