Hey, thanks for the report. This is a known issue with MCP and the new Let’s Encrypt R12 certificates. I’ve seen a few reports. Cursor can’t verify these new intermediate certificates yet, even though they’re valid.
A similar case is here: Cursor seems to me missing some CA certificates? (Can't connect to some HTTPS servers)
The bug is logged, but there’s no ETA for a fix yet. Your report helps us prioritize. I’ll add that Fibery is affected too.
Sadly, there’s no workaround right now. If I find any status updates, I’ll post them here.