ERR_SSL_PROTOCOL_ERROR

[Iyad10]

I am getting this error on the different browsers (edge, chrome).

In the log file I am seeing the following repetitvely:

DnsCryptProxy IPv4: dnscrypt-proxy [20812]: [ERROR] Unable to retrieve server certificates

Dns Protection: NetworkProbe: refreshing system resolver check cache

Dns Protection: NetworkProbe: no response from X.X.X.X

Anyone faced a similar issue?

[rotblitz]

It looks like you have a dnscrypt-proxy installed and running, but it is not configured correctly, or the command parameters are not correct.  It depends on the OS and version about how to fix it.

[Iyad10]

Thanks for the reply,

We have AnyConnect Umbrella Agent 4.9 installed on a windows 10 machine. The user is not able to browse the internet. I understand that dnscrypt is failing but not sure what is causing the failure. This failure to browse the internet is happening on a customer wifi.

Any idea how to look into the root cause?

[rotblitz]

I am a home user and cannot help with Umbrella, just with OpenDNS.  Your best bet is to open a ticket with much details from the Umbrella forum, link "Submit a request".

https://support.umbrella.com/hc/en-us/requests/new

[georgekeys]

@animeworld It sounds very similar to a DNS filtering or certificate retrieval issue rather than a browser problem. I have seen cases where `dnscrypt-proxy` repeatedly fails to fetch server certificates, which then causes `ERR_SSL_PROTOCOL_ERROR` across multiple browsers because they all rely on the same network stack. I'd start by checking whether DNS protection or any filtering service is blocking certificate retrieval, and if possible, temporarily disable it to confirm. If you come across any troubleshooting guide or relevant URL, please share it here—it would help narrow down the exact cause.