I have the following error while trying to connect SQL Server:

> 
> [Microsoft][ODBC Driver 18 for SQL Server]SSL Provider: [error:1416F086:SSL routines:tls\_process\_server\_certificate:certificate verify failed:self signed certificate]
> 
> 
> 

I'm on Ubuntu 20, PHP 7.4 FPM, nginx.

> 
> Server Microsoft SQL Server [11.00.3128
> Microsoft SQL Server 2012 (SP1) - 11.0.3128.0 (X64)
> Dec 28 2012 20:23:12
> Copyright (c) Microsoft Corporation
> Standard Edition (64-bit) on Windows NT 6.2 (Build 9200: ) (Hypervisor)
> ]
> 
> 
> 

When I:

```
openssl s_client -connect myserverip:1433 -tls1

```

I get:

> 
> CONNECTED(00000003)
> 
> 
> 

My openssl library version is:

> 
> OpenSSL 1.1.1f 31 Mar 2020 (Library: OpenSSL 1.1.1k 25 Mar 2021)
> 
> 
> 

I have tried many things, like forcing system to use TLS1 in /etc/ssl/openssl.cnf or nginx configuration to downgrade to tls1.