diff --git a/parser/aws/AWS_Interface.hpp b/parser/aws/AWS_Interface.hpp
index 78b528e..99f8736 100644
--- a/parser/aws/AWS_Interface.hpp
+++ b/parser/aws/AWS_Interface.hpp
@@ -4,6 +4,7 @@
 #include "ParserInterface.hpp"
 
 #include <memory>
+#include <string>
 
 namespace NCBI
 {
diff --git a/parser/gcp/GCP_Interface.hpp b/parser/gcp/GCP_Interface.hpp
index 6c9ec6f..30bdc28 100644
--- a/parser/gcp/GCP_Interface.hpp
+++ b/parser/gcp/GCP_Interface.hpp
@@ -4,6 +4,7 @@
 #include "ParserInterface.hpp"
 
 #include <memory>
+#include <string>
 
 namespace NCBI
 {
diff --git a/parser/op/OP_Interface.hpp b/parser/op/OP_Interface.hpp
index 742e7bc..cd5ebb1 100644
--- a/parser/op/OP_Interface.hpp
+++ b/parser/op/OP_Interface.hpp
@@ -4,6 +4,7 @@
 #include "ParserInterface.hpp"
 
 #include <memory>
+#include <string>
 
 namespace NCBI
 {
diff --git a/parser/op/op_parser.y b/parser/op/op_parser.y
index d376ae6..29fe08d 100644
--- a/parser/op/op_parser.y
+++ b/parser/op/op_parser.y
@@ -67,8 +67,7 @@ log_onprem
       referer SPACE
       { op_start_UserAgent( scanner ); } agent { op_pop_state( scanner ); } SPACE
       forwarded  SPACE
-      port  SPACE
-      req_len
+      tail
     {
         // in case the productions did not find vers/path, set them here to make them at least empty in the ouput
         SET_VALUE( OPReceiver::vers, EmptyTSTR );
@@ -76,6 +75,33 @@ log_onprem
     }
     ;
 
+tail
+    : tail_elem
+    | tail SPACE tail_elem
+    ;
+
+tail_elem
+    : port
+    | req_len
+    | STR
+    | I64
+    | quoted_freeform
+    ;
+
+quoted_freeform
+    : QUOTE freeform QUOTE;
+
+freeform
+    : freeform_elem
+    | freeform freeform_elem
+    ;
+
+freeform_elem
+    : QSTR
+    | I64
+    | SPACE
+    ;
+
 log_onprem_err
     : ip error
     ;
diff --git a/parser/op/op_test_parse.cpp b/parser/op/op_test_parse.cpp
index 78d319d..f94bd0b 100644
--- a/parser/op/op_test_parse.cpp
+++ b/parser/op/op_test_parse.cpp
@@ -399,6 +399,12 @@ TEST_F( OPTestFixture, parse_path_with_url_encoded_slash_in_extension )
     ASSERT_EQ( "", extract_value( res, "extension" ) );
 }
 
+TEST_F( OPTestFixture, parse_error )
+{
+    std::string res = try_to_parse_good( "34.140.130.14 - - [07/May/2025:23:48:24 -0400] \"ftp.ncbi.nih.gov\" \"GET /1000genomes/ftp/phase3/data/HG02025/sequence_read/SRR821984_2.filt.fastq.gz HTTP/1.1\" 200 111014168 0 \"-\" \"Mozilla/5.0 (Windows NT 10.0; rv:78.0) Gecko/20100101 Firefox/78.0\" \"-\" -pct 134311 X \"NCBI-SID: -\" port=443 885 80688 application/x-gzip" );
+    ASSERT_EQ( "443", extract_value( res, "port" ) );
+}
+
 extern "C"
 {
     int main ( int argc, const char * argv [], const char * envp []  )