What this error means
The browser could not create a valid HTTPS connection for the hostname. The browser or proxy message describes the symptom, not necessarily the root cause. HostWithShery therefore checks the TLS, certificate and HTTPS evidence that can be observed publicly before recommending a configuration change.
Most likely causes
These are the first explanations to test because each can produce this exact symptom. Treat them as hypotheses until the matching public evidence is present.
- Certificate/TLS failure — Test the hostname actually requested, its certificate dates and SAN coverage, and the TLS handshake. Root and www can serve different certificates.
- Port 443 misconfiguration — Verify port 443 misconfiguration from the public Internet and compare it with the value the responsible provider says should be live.
- Proxy/origin SSL mismatch — Test the hostname actually requested, its certificate dates and SAN coverage, and the TLS handshake. Root and www can serve different certificates.
What to check on your domain
Use the embedded scan to compare the failing layer with adjacent layers that can produce the same visible error. This prevents a DNS change from being used to “fix” a TLS problem, or an SSL-mode change from masking an origin failure.
- Certificate/TLS failure — Test the hostname actually requested, its certificate dates and SAN coverage, and the TLS handshake. Root and www can serve different certificates.
- Port 443 misconfiguration — Verify port 443 misconfiguration from the public Internet and compare it with the value the responsible provider says should be live.
- Proxy/origin SSL mismatch — Test the hostname actually requested, its certificate dates and SAN coverage, and the TLS handshake. Root and www can serve different certificates.
- Run the SSL checker — Test the hostname actually requested, its certificate dates and SAN coverage, and the TLS handshake. Root and www can serve different certificates.
- Compare root and www — Verify compare root and www from the public Internet and compare it with the value the responsible provider says should be live.
Fixes in the recommended order
Change the smallest confirmed layer first. Preserve working DNS and mail records, document the current value, apply one repair, and then retest before moving to the next possibility.
- 1. Run the SSL checker. Confirm the public result after this step before making another unrelated change.
- 2. Compare root and www. Confirm the public result after this step before making another unrelated change.
- 3. Repair the TLS endpoint. Confirm the public result after this step before making another unrelated change.
How to confirm the repair
HTTPS should complete for the exact hostname, the certificate should be valid for that hostname, and root/www should follow the intended canonical redirect without a TLS error.
If the error remains
Capture the checked hostname, exact timestamp, final DNS addresses, redirect/TLS result and the failing public status before escalating. That evidence gives a hosting or provider support team something testable instead of only the browser message. If results differ by resolver or network, include those differences rather than assuming the failure is universal.
What not to change
Do not replace nameservers, delete unrelated mail records, disable security controls, remove IPv6 blindly or purge the entire configuration merely because this message appears. Diagnose the failing layer first; broad changes can turn one isolated fault into several independent faults.
Technical references
These primary standards and provider documents are used to verify the behavior described on this page. Provider dashboards can change, so use the current official value for tenant-specific DNS records rather than copying an example from another account.