I’m unable to connect to the mailchimp newsletter domain: https://us19.campaign-archive.com/
I thought this might be a DNS issue so was about to test it using https://tools.keycdn.com/performance , however that’s also being blocked.
Both are being flagged as phishing URLs in Avast, which seems odd. I haven’t been able to find any other details in virustotal for example that would indicate these as being malicious links.