diff --git a/td/telegram/net/NetQueryCreator.cpp b/td/telegram/net/NetQueryCreator.cpp
index 5c94e48dd..c58f55ca9 100644
--- a/td/telegram/net/NetQueryCreator.cpp
+++ b/td/telegram/net/NetQueryCreator.cpp
@@ -6,6 +6,7 @@
 //
 #include "td/telegram/net/NetQueryCreator.h"
 
+#include "td/utils/format.h"
 #include "td/utils/Gzip.h"
 #include "td/utils/logging.h"
 
@@ -16,7 +17,8 @@ NetQueryCreator::Ptr NetQueryCreator::create(uint64 id, const Storer &storer, Dc
                                              double total_timeout_limit) {
   BufferSlice slice(storer.size());
   auto real_size = storer.store(slice.as_slice().ubegin());
-  CHECK(real_size == slice.size());
+  CHECK(real_size == slice.size()) << real_size << " " << slice.size() << " "
+                                   << format::as_hex_dump<4>(Slice(slice.as_slice()));
 
   // TODO: magic constant
   if (slice.size() < (1 << 8)) {
diff --git a/td/telegram/net/PublicRsaKeyShared.cpp b/td/telegram/net/PublicRsaKeyShared.cpp
index 44169c66d..f95b22296 100644
--- a/td/telegram/net/PublicRsaKeyShared.cpp
+++ b/td/telegram/net/PublicRsaKeyShared.cpp
@@ -20,7 +20,7 @@ PublicRsaKeyShared::PublicRsaKeyShared(DcId dc_id) : dc_id_(dc_id) {
   }
   auto add_pem = [this](CSlice pem) {
     auto r_rsa = RSA::from_pem(pem);
-    CHECK(r_rsa.is_ok()) << r_rsa.error();
+    CHECK(r_rsa.is_ok()) << r_rsa.error() << " " << pem;
 
     if (r_rsa.is_ok()) {
       this->add_rsa(r_rsa.move_as_ok());