diff --git a/src/core/ngx_conf_file.c b/src/core/ngx_conf_file.c
index c60d5fb41..ea1dcebfb 100644
--- a/src/core/ngx_conf_file.c
+++ b/src/core/ngx_conf_file.c
@@ -1336,7 +1336,7 @@ ngx_conf_set_enum_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
         return NGX_CONF_OK;
     }
 
-    ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
+    ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                        "invalid value \"%s\"", value[1].data);
 
     return NGX_CONF_ERROR;
@@ -1378,7 +1378,7 @@ ngx_conf_set_bitmask_slot(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
         }
 
         if (mask[m].name.len == 0) {
-            ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                "invalid value \"%s\"", value[i].data);
 
             return NGX_CONF_ERROR;
diff --git a/src/event/ngx_event_openssl.c b/src/event/ngx_event_openssl.c
index 1cbfdf262..90a5cef85 100644
--- a/src/event/ngx_event_openssl.c
+++ b/src/event/ngx_event_openssl.c
@@ -3656,13 +3656,13 @@ ngx_openssl_engine(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
     engine = ENGINE_by_id((char *) value[1].data);
 
     if (engine == NULL) {
-        ngx_ssl_error(NGX_LOG_WARN, cf->log, 0,
+        ngx_ssl_error(NGX_LOG_EMERG, cf->log, 0,
                       "ENGINE_by_id(\"%V\") failed", &value[1]);
         return NGX_CONF_ERROR;
     }
 
     if (ENGINE_set_default(engine, ENGINE_METHOD_ALL) == 0) {
-        ngx_ssl_error(NGX_LOG_WARN, cf->log, 0,
+        ngx_ssl_error(NGX_LOG_EMERG, cf->log, 0,
                       "ENGINE_set_default(\"%V\", ENGINE_METHOD_ALL) failed",
                       &value[1]);
 
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index 7e4b3c549..8ddc4e3e9 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -5717,14 +5717,14 @@ ngx_http_upstream_add(ngx_conf_t *cf, ngx_url_t *u, ngx_uint_t flags)
         }
 
         if ((uscfp[i]->flags & NGX_HTTP_UPSTREAM_CREATE) && !u->no_port) {
-            ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                "upstream \"%V\" may not have port %d",
                                &u->host, u->port);
             return NULL;
         }
 
         if ((flags & NGX_HTTP_UPSTREAM_CREATE) && !uscfp[i]->no_port) {
-            ngx_log_error(NGX_LOG_WARN, cf->log, 0,
+            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                           "upstream \"%V\" may not have port %d in %s:%ui",
                           &u->host, uscfp[i]->port,
                           uscfp[i]->file_name, uscfp[i]->line);
diff --git a/src/mail/ngx_mail_ssl_module.c b/src/mail/ngx_mail_ssl_module.c
index 11e428cb9..fbc9bc74b 100644
--- a/src/mail/ngx_mail_ssl_module.c
+++ b/src/mail/ngx_mail_ssl_module.c
@@ -488,7 +488,7 @@ ngx_mail_ssl_enable(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
     }
 
     if (scf->enable && (ngx_int_t) scf->starttls > NGX_MAIL_STARTTLS_OFF) {
-        ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                            "\"starttls\" directive conflicts with \"ssl on\"");
         return NGX_CONF_ERROR;
     }
@@ -514,7 +514,7 @@ ngx_mail_ssl_starttls(ngx_conf_t *cf, ngx_command_t *cmd, void *conf)
     }
 
     if (scf->enable == 1 && (ngx_int_t) scf->starttls > NGX_MAIL_STARTTLS_OFF) {
-        ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
+        ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                            "\"ssl\" directive conflicts with \"starttls\"");
         return NGX_CONF_ERROR;
     }
diff --git a/src/stream/ngx_stream_upstream.c b/src/stream/ngx_stream_upstream.c
index 0c5978031..2a164fc8c 100644
--- a/src/stream/ngx_stream_upstream.c
+++ b/src/stream/ngx_stream_upstream.c
@@ -586,14 +586,14 @@ ngx_stream_upstream_add(ngx_conf_t *cf, ngx_url_t *u, ngx_uint_t flags)
         }
 
         if ((uscfp[i]->flags & NGX_STREAM_UPSTREAM_CREATE) && !u->no_port) {
-            ngx_conf_log_error(NGX_LOG_WARN, cf, 0,
+            ngx_conf_log_error(NGX_LOG_EMERG, cf, 0,
                                "upstream \"%V\" may not have port %d",
                                &u->host, u->port);
             return NULL;
         }
 
         if ((flags & NGX_STREAM_UPSTREAM_CREATE) && !uscfp[i]->no_port) {
-            ngx_log_error(NGX_LOG_WARN, cf->log, 0,
+            ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                           "upstream \"%V\" may not have port %d in %s:%ui",
                           &u->host, uscfp[i]->port,
                           uscfp[i]->file_name, uscfp[i]->line);