diff --git a/src/http/modules/ngx_http_grpc_module.c b/src/http/modules/ngx_http_grpc_module.c
index a64658f..617814e 100644
--- a/src/http/modules/ngx_http_grpc_module.c
+++ b/src/http/modules/ngx_http_grpc_module.c
@@ -4906,8 +4906,9 @@
         return NGX_ERROR;
     }
 
-    if (glcf->upstream.ssl_certificate) {
-
+    if (glcf->upstream.ssl_certificate
+        && glcf->upstream.ssl_certificate->value.len)
+    {
         if (glcf->upstream.ssl_certificate_key == NULL) {
             ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                           "no \"grpc_ssl_certificate_key\" is defined "
diff --git a/src/http/modules/ngx_http_proxy_module.c b/src/http/modules/ngx_http_proxy_module.c
index e8df555..bb93030 100644
--- a/src/http/modules/ngx_http_proxy_module.c
+++ b/src/http/modules/ngx_http_proxy_module.c
@@ -4955,8 +4955,9 @@
         return NGX_ERROR;
     }
 
-    if (plcf->upstream.ssl_certificate) {
-
+    if (plcf->upstream.ssl_certificate
+        && plcf->upstream.ssl_certificate->value.len)
+    {
         if (plcf->upstream.ssl_certificate_key == NULL) {
             ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                           "no \"proxy_ssl_certificate_key\" is defined "
diff --git a/src/http/modules/ngx_http_uwsgi_module.c b/src/http/modules/ngx_http_uwsgi_module.c
index 5078ef7..1dcee1e 100644
--- a/src/http/modules/ngx_http_uwsgi_module.c
+++ b/src/http/modules/ngx_http_uwsgi_module.c
@@ -2487,8 +2487,9 @@
         return NGX_ERROR;
     }
 
-    if (uwcf->upstream.ssl_certificate) {
-
+    if (uwcf->upstream.ssl_certificate
+        && uwcf->upstream.ssl_certificate->value.len)
+    {
         if (uwcf->upstream.ssl_certificate_key == NULL) {
             ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                           "no \"uwsgi_ssl_certificate_key\" is defined "
diff --git a/src/http/ngx_http_upstream.c b/src/http/ngx_http_upstream.c
index ead3715..3ae822b 100644
--- a/src/http/ngx_http_upstream.c
+++ b/src/http/ngx_http_upstream.c
@@ -1690,8 +1690,10 @@
         }
     }
 
-    if (u->conf->ssl_certificate && (u->conf->ssl_certificate->lengths
-                                     || u->conf->ssl_certificate_key->lengths))
+    if (u->conf->ssl_certificate
+        && u->conf->ssl_certificate->value.len
+        && (u->conf->ssl_certificate->lengths
+            || u->conf->ssl_certificate_key->lengths))
     {
         if (ngx_http_upstream_ssl_certificate(r, u, c) != NGX_OK) {
             ngx_http_upstream_finalize_request(r, u,
diff --git a/src/stream/ngx_stream_proxy_module.c b/src/stream/ngx_stream_proxy_module.c
index 934e7d8..683f7d7 100644
--- a/src/stream/ngx_stream_proxy_module.c
+++ b/src/stream/ngx_stream_proxy_module.c
@@ -1069,8 +1069,10 @@
         }
     }
 
-    if (pscf->ssl_certificate && (pscf->ssl_certificate->lengths
-                                  || pscf->ssl_certificate_key->lengths))
+    if (pscf->ssl_certificate
+        && pscf->ssl_certificate->value.len
+        && (pscf->ssl_certificate->lengths
+            || pscf->ssl_certificate_key->lengths))
     {
         if (ngx_stream_proxy_ssl_certificate(s) != NGX_OK) {
             ngx_stream_proxy_finalize(s, NGX_STREAM_INTERNAL_SERVER_ERROR);
@@ -2225,8 +2227,9 @@
         return NGX_ERROR;
     }
 
-    if (pscf->ssl_certificate) {
-
+    if (pscf->ssl_certificate
+        && pscf->ssl_certificate->value.len)
+    {
         if (pscf->ssl_certificate_key == NULL) {
             ngx_log_error(NGX_LOG_EMERG, cf->log, 0,
                           "no \"proxy_ssl_certificate_key\" is defined "