After Effects 25.2.2 (Win) - CEP Remote Debugging Port Not Opening (netstat Confirms No Listening Pr

Hello everyone,

I'm encountering a persistent issue where I'm unable to use remote debugging for my CEP extension in After Effects 25.2.2 on Windows. The core problem is that After Effects does not seem to open or listen on the specified remote debugging port. I'm hoping someone in the community has encountered this or can offer new insights, as extensive troubleshooting has not yet resolved it.

My Environment:

• Operating System: Windows (User: Pro980)
• Adobe After Effects Version: 25.2.2
• CEP Version (inferred from logs): CEP 12 (e.g., CEP12-AEFT.log shows PlugPlug version 12.0.1.2)

Problem Description: When my CEP extension panel (or even a minimal test panel) is loaded in After Effects, I cannot connect to the configured remote debugging port (e.g., http://localhost:8089, http://127.0.0.1:8089, or other ports tested). The browser consistently shows a "site can't be reached" error. Critically, using the netstat -ano | findstr ":[PORT_NUMBER]" command in Windows command line confirms that there is no process listening on the configured debug port when After Effects and the panel are active.

Troubleshooting Steps Performed (Exhaustively):

Correct Extension Path: Confirmed the extension is in the correct user-specific folder: C:\Users\Pro980\AppData\Roaming\Adobe\CEP\extensions.

CSXS/manifest.xml Configuration:

• Validated ExtensionBundleId and Extension Id.
• Ensured MainPath (e.g., ./client/index.html) and ScriptPath (for my main extension) are correct. Confirmed ./ prefix is necessary for the panel to load.
• <CEFCommandLine> includes <Parameter>--remote-debugging-port=[PORT]</Parameter> (tried 8089, 8091, 8092).
• For my main extension, <Parameter>--enable-nodejs</Parameter> and <Parameter>--mixed-context</Parameter> are included (removing them breaks panel UI functionality, so they seem necessary for the panel itself).

CSXS/.debug File:

• Correctly formatted XML specifying the panel's Extension Id and the Host Name="AEFT" with the matching Port number as defined in manifest.xml.

Windows Firewall:

• "Adobe After Effects 2025" application is explicitly allowed for Private and Public networks.
• Specific inbound rules were created to "Allow" TCP connections for all tested ports (8089, 8091, 8092) across all network profiles (Domain, Private, Public).
• netstat confirmed no other applications were using the specified ports, ruling out a direct port conflict.

Registry Settings:

• PlayerDebugMode (String Value REG_SZ) has been verified and set to 1 in all found CSXS version keys under HKEY_CURRENT_USER\Software\Adobe, specifically including CSXS.11 and CSXS.12.
• The computer was fully restarted after these registry changes.

Conflicting Extensions:

• All other CEP extensions were temporarily removed from both user-specific (AppData\Roaming...) and system-level (Program Files (x86)\Common Files...) extension folders to ensure no conflicts. This did not resolve the issue.

Different Ports Tested: Ports 8089, 8091, and 8092 were all tested with corresponding changes in manifest.xml, .debug file, and firewall rules. None worked.

CEP Log Files Reviewed:

• Inspected CEP12-AEFT.log, CEPHtmlEngine12-AEFT-[version]-com.[extensionId].ui.log, and the ...-renderer.log.
• No explicit errors such as "failed to start debug server," "port in use," or other direct indicators of a debug port initialization failure specific to the debug service were found. The main ...ui.log typically only shows an "Injecting cep_node" message as the last entry during these attempts.

Key Diagnostic: Minimal Test Extension Also Fails To isolate the problem from my main extension's complexity, I created an absolutely minimal CEP extension:

• New, unique Bundle ID and Panel ID.
• Simple manifest.xml pointing to a basic index.html.
• CEFCommandLine contained only <Parameter>--remote-debugging-port=8092</Parameter>.
• Corresponding .debug file for port 8092.
• New firewall rule for port 8092.

Result: This "Minimal Test Panel" loads and displays its simple HTML content correctly within After Effects. However, its remote debugging port (8092) is also unreachable, and netstat confirms After Effects is not listening on this port either.

Conclusion & Request for Help: The failure of even a minimal test extension strongly suggests the issue is not specific to my QuickFX extension's code but likely lies with the After Effects 25.2.2 installation, the general CEP 12 environment on my Windows system, or a potential system-level conflict that's preventing After Effects from initializing any CEP debug service.

• Has anyone else experienced similar issues with remote debugging ports not opening in After Effects 25.2.x (or recent versions) on Windows?
• Are there any other known After Effects or CEP environmental variables, configuration files, or system settings (beyond what's listed above) that could influence CEP debug port initialization?
• Could this be a bug in this specific version of After Effects or CEP?

Any insights, suggestions for further diagnostics, or shared experiences would be greatly appreciated. I have an Adobe Support case open (ADB-39868579-N2V0), and a support representative has offered to forward a forum discussion link to the engineering team.

Thank you!