AI Assistant fails on every prompt in Premiere Pro Beta 26.5.0 Build 42

I am experiencing a problem with the new AI Assistant in Premiere Pro Beta.

The Assistant panel loads correctly, I can create new chats, and messages are sent successfully. However, every prompt immediately returns the following error:

"There was an issue processing your request. Please try again. If the issue persists, please start a new chat."

The error occurs with every prompt, including very simple requests that do not require media analysis.

Examples:

• "What version of Premiere Pro am I using?"
• "What can you do?"
• "Give me an example of what you can do."

The error appears almost instantly after sending the prompt.

System Information:

• Premiere Pro Beta 26.5.0 (Build 42)
• Windows 11
• Creative Cloud Pro subscription
• Generative AI features included in plan
• Adobe Firefly works normally in the browser
• Creative Cloud Desktop is up to date
• System Compatibility Report shows "No conflicts to report"

Troubleshooting already performed:

• Signed out and back into Adobe Creative Cloud
• Created multiple new Assistant chats
• Tested with and without projects open
• Tested simple prompts that do not require timeline analysis
• Verified Firefly image generation works correctly
• Verified active subscription and AI entitlement
• Checked System Compatibility Report (no issues found)

Expected Behavior:

The Assistant should process prompts and return responses.

Actual Behavior:

Every prompt fails immediately with the generic processing error message.

Could someone confirm whether this is a known issue with Build 42 or if there are additional logs/settings I should check?

Thank you.