SSL 모듈 활성화 명령어를 입력하면 아파치 재시작 시 에러가 납니다.

아파치 2를 사용중입니다.

재시작 시 메시지 : 

apache2: Could not reliably determine the server's fully qualified domain name, using 127.0.0.1. Set the 'ServerName' directive globally to suppress this message

Action 'start' failed.

The Apache error log may have more information.

 * The apache2 instance did not start within 20 seconds. Please read the log files to discover problems

로그 :

[Wed Aug 12 05:16:02.310020 2015] [core:notice] [pid 8214] AH00094: Command line: '/usr/sbin/apache2'

[Wed Aug 12 05:19:34.798767 2015] [mpm_prefork:notice] [pid 8214] AH00169: caught SIGTERM, shutting down

[Wed Aug 12 05:19:35.978602 2015] [ssl:emerg] [pid 8369] AH02241: Init: Unable to read server certificate from file /etc/apache2/server.csr

[Wed Aug 12 05:19:35.978749 2015] [ssl:emerg] [pid 8369] SSL Library Error: error:0D0680A8:asn1 encoding routines:ASN1_CHECK_TLEN:wrong tag

[Wed Aug 12 05:19:35.978786 2015] [ssl:emerg] [pid 8369] SSL Library Error: error:0D07803A:asn1 encoding routines:ASN1_ITEM_EX_D2I:nested asn1 error (Type=X509)

[Wed Aug 12 05:19:35.978809 2015] [ssl:emerg] [pid 8369] AH02312: Fatal error initialising mod_ssl, exiting.

왜 이러는걸까요. 도와주시면 감사드리겠습니다.