diff --git a/src/mail/ngx_mail_auth_http_module.c b/src/mail/ngx_mail_auth_http_module.c
index f7ad308..acd0665 100644
--- a/src/mail/ngx_mail_auth_http_module.c
+++ b/src/mail/ngx_mail_auth_http_module.c
@@ -1302,7 +1302,7 @@
 
     ahcf = ngx_pcalloc(cf->pool, sizeof(ngx_mail_auth_http_conf_t));
     if (ahcf == NULL) {
-        return NGX_CONF_ERROR;
+        return NULL;
     }
 
     ahcf->timeout = NGX_CONF_UNSET_MSEC;
diff --git a/src/mail/ngx_mail_core_module.c b/src/mail/ngx_mail_core_module.c
index d0addb0..bd2c916 100644
--- a/src/mail/ngx_mail_core_module.c
+++ b/src/mail/ngx_mail_core_module.c
@@ -120,20 +120,20 @@
 
     cmcf = ngx_pcalloc(cf->pool, sizeof(ngx_mail_core_main_conf_t));
     if (cmcf == NULL) {
-        return NGX_CONF_ERROR;
+        return NULL;
     }
 
     if (ngx_array_init(&cmcf->servers, cf->pool, 4,
                        sizeof(ngx_mail_core_srv_conf_t *))
         != NGX_OK)
     {
-        return NGX_CONF_ERROR;
+        return NULL;
     }
 
     if (ngx_array_init(&cmcf->listen, cf->pool, 4, sizeof(ngx_mail_listen_t))
         != NGX_OK)
     {
-        return NGX_CONF_ERROR;
+        return NULL;
     }
 
     return cmcf;
diff --git a/src/mail/ngx_mail_proxy_module.c b/src/mail/ngx_mail_proxy_module.c
index 193df8a..b408ed7 100644
--- a/src/mail/ngx_mail_proxy_module.c
+++ b/src/mail/ngx_mail_proxy_module.c
@@ -1061,7 +1061,7 @@
 
     pcf = ngx_pcalloc(cf->pool, sizeof(ngx_mail_proxy_conf_t));
     if (pcf == NULL) {
-        return NGX_CONF_ERROR;
+        return NULL;
     }
 
     pcf->enable = NGX_CONF_UNSET;
diff --git a/src/mail/ngx_mail_ssl_module.c b/src/mail/ngx_mail_ssl_module.c
index 4e2bda5..1fcdb75 100644
--- a/src/mail/ngx_mail_ssl_module.c
+++ b/src/mail/ngx_mail_ssl_module.c
@@ -166,7 +166,7 @@
 
     scf = ngx_pcalloc(cf->pool, sizeof(ngx_mail_ssl_conf_t));
     if (scf == NULL) {
-        return NGX_CONF_ERROR;
+        return NULL;
     }
 
     /*