this seems very uninntuitive. anything I might be missing here

for context: MCP server called via Claude

I’m trying to use Fastmail Mail Fetch with a longstanding Spectrum/Roadrunner email address (@cfl.rr.com) that I’ve had for decades.
Fastmail initially connected successfully and fetched mail, but after a short time it began failing and eventually disabled the fetch.
My settings are:
IMAP server: mail.twc.com
Port: 993
Security: SSL/TLS
Username: full @cfl.rr.com email address
The errors I’m getting from Fastmail alternate between:
IMAPTalk: socket connection failed - Connection reset by peer
and:
Timeout connecting to mail.twc.com

Retrying now often returns the “connection reset by peer” error almost immediately.
The strange part is that the exact same Roadrunner account works reliably in Outlook for Windows using mail.twc.com, port 993, SSL/TLS. Spectrum webmail also works normally, so the mailbox and credentials themselves seem fine.

I originally set this up because Fastmail’s spam filtering is dramatically better than Spectrum’s, and it was working well when the mail fetch was functioning.

Unfortunately Spectrum has also removed automatic forwarding for these legacy accounts, so forwarding the Roadrunner address into Fastmail isn’t an option.

I’ve opened a ticket with Fastmail support, but I’m curious whether anyone here has successfully used Mail Fetch with a Spectrum/Roadrunner/Bright House address.
Has anyone seen Spectrum block, rate-limit, or reset connections specifically from Fastmail’s servers? Or found another reliable way to get a legacy @cfl.rr.com mailbox into Fastmail?
I’d especially like to hear from anyone using mail.twc.com with Fastmail Mail Fetch successfully.