Debugger Error "Error while polling result"

Summary
The pgAdmin 4 debugger fails during execution of a stored procedure/function, returning a "Debugger Error: Error while polling result" popup. Browser console logs indicate a 500 Internal Server Error on the /debugger/poll_result and /debugger/start_listener endpoints.
2. Environment Information
• pgAdmin 4 Version: (9.14)
• Mode: Desktop / Server (whichever you are using)
• Browser: Chrome (indicated by DevTools)
• OS: Windows
• PostgreSQL Version: (e.g., postgresql-18.3-3-windows-x64)
• pldbgapi extension version: (Run SELECT * FROM pg_extension WHERE extname = 'pldbgapi';)

3. Steps to Reproduce
4. Open pgAdmin 4 and connect to a database where the pldbgapi extension is installed and added to shared_preload_libraries.
5. Navigate to Schemas > [Schema Name] > Procedures (or Functions).
6. Right-click a procedure/Function (e.g., sp_f... as seen in your screenshot) and select Debugging > Setbreak point
7. Again select Debugging > Setbreak point.
8. Observe the debugger interface initializing.
9. Actual Behavior: A "Debugger Error" dialog appears stating "Error while polling result," and the debugger fails to advance. The browser console shows AxiosError: Request failed with status code 500.
10. Expected Behavior: The debugger should initialize, stop at the first line of code, and allow stepping through the logic.

4. Error Details (From DevTools)
   • Endpoint: /debugger/poll_result/[SessionID]
   • Status Code: 500 (Internal Server Error)
   • Console Trace: AxiosError: Request failed with status code 500 at Ve (vendor.others.js...)

Screenshot:

Reproduce the debugger failure using the listed procedure steps and inspect the /debugger/poll_result/[SessionID] and /debugger/start_listener requests alongside the server error details. Trace the 500 response to its backend cause; done means the debugger initializes, stops at the first line, and supports stepping without the polling error.