I try to migrade from odoo15 to 16 following the document  Introduction — OpenUpgrade 16.0 documentation (oca.github.io) .

But at the exeution phase the progress seems to hang at the connection phase, so I ask for help to solve this issue.

Below is the procedure:

1. install opengrade: this is done without any error message
2. download openugrade-16.0 and put it in the path below \\wsl.localhost\Ubuntu\usr\src\odoo16\OpenUpgrade-16.0
3. set odoo15_16.conf, with the following content:
1. db_host = localhost
2. db_port = 8069
3. db_user = my_account_name
4. db_password = my_password
5. addons_path = /usr/src/odoo16/odoo-16.0/addons,/usr/src/odoo16/OpenUpgrade-16.0
4. I use screen to run odoo15 in one screen and run upgrade in another screen
5. In the screen running odoo15, I used database named local_db1 which contains the data I established in odoo15 and I want to upgrade to odoo16
6. In another screen I run upgrade with the following command:  python3 odoo-bin -c odoo15_16.conf --update all -d local_db1 --upgrade-path= /usr/src/odoo16/OpenUpgrade-16.0/openupgrade_scripts/scripts --stop-after-init --load=base,web,openupgrade_framework
1. where local_db1 is the database established in odoo15 which I want to upgrade to odoo16
2. The message shows:
1. 2024-04-12 02:26:27,146 27512 WARNING ? py.warnings: /usr/src/odoo16/odoo-16.0/odoo/tools/config.py:: DeprecationWarning: The longpolling-port is a deprecated alias to the gevent-port option, please use the latter.
2.   File "odoo-bin", line 8, in
3.     odoo.cli.main()
4.   File "/usr/src/odoo16/odoo-16.0/odoo/cli/command.py", line 66, in main
5.     o.run(args)
6.   File "/usr/src/odoo16/odoo-16.0/odoo/cli/server.py", line 180, in run
7.     main(args)
8.   File "/usr/src/odoo16/odoo-16.0/odoo/cli/server.py", line 127, in main
9.     odoo.tools.config.parse_config(args)
10.   File "/usr/src/odoo16/odoo-16.0/odoo/tools/config.py", line 379, in parse_config
11.     self._warn_deprecated_options()
12.   File "/usr/src/odoo16/odoo-16.0/odoo/tools/config.py", line 566, in _warn_deprecated_options
13.     warnings.warn(
3. 2024-04-12 02:26:27,148 27512 INFO ? odoo: Odoo version 16.0
4. 2024-04-12 02:26:27,148 27512 INFO ? odoo: Using configuration file at /usr/src/odoo16/odoo-16.0/odoo15_16.conf
5. 2024-04-12 02:26:27,148 27512 INFO ? odoo: addons paths: ['/usr/src/odoo16/odoo-16.0/odoo/addons', '/root/.local/share/Odoo/addons/16.0', '/usr/src/odoo16/odoo-16.0/addons', '/usr/src/odoo16/OpenUpgrade-16.0']
6. 2024-04-12 02:26:27,148 27512 INFO ? odoo: upgrade path: /usr/src/odoo16/OpenUpgrade-16.0/openupgrade_scripts/scripts
7. 2024-04-12 02:26:27,148 27512 INFO ? odoo: database: admin@localhost:8069
7. But after message as shown in 6.b.g, there is no more message, neither progress info nor error message.
8. I traced the code of server.py, and know that the message 6.b.g. is issued in report_configuration(), following which is following which are other codes. However, no progress message nor error message.
9. After 1 hour, a message appear on screen of upgrade:

2024-04-12 03:27:09,468 27512 INFO ? odoo.sql_db: Connection to the database failed

1. Then I checked the log of odoo15 running on the other screen, near the time stamp is another message:

2024-04-12 03:27:09,342 120 WARNING local_db1 odoo.service.server: Thread virtual real time limit (3642/3600s) reached.

1. The real time limit is set in the paramters of running odoo15
2. From the above messages, it is clear that openupgrade is connecting with odoo15, but it seems no message is exchanged, thus when odoo15 restart due to virtual real time limit reached, openupgrade shows connection failure.
3. On odoo15 reaching virtual real time limit, odoo16 shows the following traceback with the last executed code as below
4. 1. File "/usr/local/lib/python3.8/dist-packages/psycopg2/__init__.py", line 127, in connect
   2.     conn = _connect(dsn, connection_factory=connection_factory, **kwasync)
   3. So it is very likely, the program is waiting for connection with odoo15, but no response is getten and no timeout is set, thus it keeps waiting until terminated by odoo15 restart.
   4. Another clue is that, no matter what db_user and db_password in odoo15_16.conf is set, the result is the same. I highly suspect it is the password incorrect or account incorrect that caused the hang. But why there is no error message?
5. My question is: is there any step I do not do correctly which caused this issue? 

Thank in advance, if someone could help me tell me what is wrong with my handling upgrade?