Cannot disconnect from Database Server via PgAdmin4 v9.12

Describe the bug

Cannot disconnect from Database Server with PgAdmin4 v9.12, the UI keeps the connection and the icon is stuck in disconnecting state.

To Reproduce

Steps to reproduce the behavior:

1. Access to pgAdmin 4 on Web Browser.
2. Connect to a PostgreSQL server.
3. Attempt to disconnect (right-click server > click on "Disconnect from Database").
4. Icon persist with prefix "[Disconnecting...]" and still keeping the connection.

Expected behavior

The server should disconnect and the connection icon should update, but instead remains active with prefix "[Disconnecting...]"

Error message

xxx.xxx.xxx.xxx - - [10/Feb/2026:11:15:35 +0000] "GET /dashboard/dashboard_stats/1?chart_names=session_stats,tps_stats,ti_stats,to_stats,bio_stats HTTP/1.1" 200 269 "https://pgadmin.example.com/browser/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36 Edg/144.0.0.0"
2026-02-10 11:15:38,018: ERROR  pgadmin:        404 Not Found: The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.
Traceback (most recent call last):
  File "/venv/lib/python3.14/site-packages/flask/app.py", line 917, in full_dispatch_request
    rv = self.dispatch_request()
  File "/venv/lib/python3.14/site-packages/flask/app.py", line 891, in dispatch_request
    self.raise_routing_exception(req)
    ~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^
  File "/venv/lib/python3.14/site-packages/flask/app.py", line 500, in raise_routing_exception
    raise request.routing_exception  # type: ignore[misc]
    ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/venv/lib/python3.14/site-packages/flask/ctx.py", line 362, in match_request
    result = self.url_adapter.match(return_rule=True)  # type: ignore
  File "/venv/lib/python3.14/site-packages/werkzeug/routing/map.py", line 629, in match
    raise NotFound() from None
werkzeug.exceptions.NotFound: 404 Not Found: The requested URL was not found on the server. If you entered the URL manually please check your spelling and try again.
xxx.xxx.xxx.xxx - - [10/Feb/2026:11:15:38 +0000] "DELETE /browser/database/connect/6/1/ HTTP/1.1" 404 207 "https://pgadmin.example.com/browser/" "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/144.0.0.0 Safari/537.36 Edg/144.0.0.0"

Screenshots

Desktop (please complete the following information):

• OS: Linux
• pgAdmin version: 9.12.0
• Mode: Server
• Browser : Microsoft Edge
• Package type: Container

Reproduce the disconnect flow in pgAdmin 4 version 9.12 and inspect the DELETE /browser/database/connect/6/1/ request that returns 404. Trace the disconnect entry point and verify that the server disconnects, the request succeeds, and the UI no longer shows the [Disconnecting...] state.