What you’re seeing
- The System event log fills with Schannel 36871 errors stating a fatal error occurred while creating a TLS client credential.
- An older business application, backup agent or reporting tool can no longer connect to its server or cloud service.
- The errors began right after TLS 1.0 and 1.1 were disabled or a security hardening change was applied.
- Secure connections to some websites or services fail while others work normally.
Common causes
Every environment is different, but these are the causes our engineers find most often:
- TLS 1.0 and 1.1 were turned off, and an application built on older .NET Framework or libraries isn't set to use TLS 1.2.
- System-wide settings that let older .NET applications follow the operating system's default TLS versions aren't in place.
- The cipher suites allowed on the computer don't overlap with the ones the remote server requires.
- The machine certificate's private key can't be read by the system account, so a client credential can't be created.
- An older Windows release is missing the updates some components need to support TLS 1.2.
Why it matters
Disabling outdated TLS is a sound security step that insurers and auditors expect, but it can quietly break the applications a business depends on: payment integrations, backups, accounting sync and line-of-business software. Failed backups are especially dangerous because nobody notices until a restore is needed. Re-enabling old protocols to make the errors go away reopens known weaknesses, so the goal is to bring the failing software up to modern standards.
How AskTechGurus fixes it
Skip the trial and error. A certified engineer works on your actual system, finds the root cause, and fixes it properly.
Tell us what’s happening
Submit a ticket in about two minutes. Paste the error, describe what changed, and pick your tier. No charge to submit.
A certified engineer diagnoses it
A vetted, US-based systems engineer claims your ticket, usually within minutes during business hours, and investigates over a secure remote session you can watch and end at any time.
Fixed and verified with you
The engineer resolves the root cause and confirms with you that it’s working. You don’t just get a workaround, and you get a plain-English summary of what was wrong.
Pay only when it’s resolved
Fixed price from $99, invoiced only after you approve the fix. If it isn’t resolved, you don’t pay.
Frequently asked questions
Was turning off old TLS versions a mistake?
No, it's the right direction for security. The errors mean some software hasn't caught up, and that software can usually be brought into line without turning old protocols back on.
How do we know which systems are affected?
Event logs and failed connections point to the specific applications involved. The engineer identifies them and gives you a plain-English summary of what was wrong.