@vorraluck, Following is the error I see, which points to the parameter 'SamplePassword123'. You're missing "=" sign in this parameter as the error hints.

# openssl req -new -sha256 -nodes -newkey rsa:2048 -config /tmp/openssl.cnf
error on line 13 of /tmp/openssl.cnf
140163633919888:error:0E079065:configuration file routines:DEF_LOAD_BIO:missing equal sign:conf_def.c:345:line 13

Change SamplePassword123 to SamplePassword = 123. Once the change is made, both the private key and the CSR file can be created. 

[root@node1 ~]# openssl req -new -sha256 -nodes -newkey rsa:2048 -config <(
>
> cat <<-EOF
>
> [req]
>
> default_bits = 2048
>
> prompt = no
>
> default_md = sha256
>
> req_extensions = req_ext
>
> distinguished_name = dn
>
> SamplePassword = 123
>
> [ dn ]
>
> C=TH
>
> ST=Bangkok
>
> L=Chaxxx
>
> O=xtac Public Company Limited
>
> OU=Enterprise Service Support
>
> emailAddress=john.doe@xtac.co.th
>
> CN = rs-xxx-hmb-201.xtac.dev
>
>
>
> [ req_ext ]
>
> subjectAltName = @alt_names
>
>
>
> [ alt_names ]
>
> DNS.1 = rs-xxx-hmb-201
>
> DNS.2 = rs-xxx-hmb-201.xtac.dev
>
>
>
> EOF
>
> )
Generating a 2048 bit RSA private key
.+++
.....................................................................................................................................................................................................................+++
writing new private key to stdout
-----BEGIN PRIVATE KEY-----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-----END PRIVATE KEY-----
-----
-----BEGIN CERTIFICATE REQUEST-----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-----END CERTIFICATE REQUEST-----
[root@node1 ~]#

Cheers! 

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