Update title format

Author: Clare-Zheng82

articles/data-factory/connector-troubleshoot-ftp-sftp-http.md

@@ -182,7 +182,7 @@ This article provides suggestions to troubleshoot common problems with the FTP,
     - diffie-hellman-group14-sha1
     - diffie-hellman-group1-sha1
 
-## Error Code: SftpInvalidHostKeyFingerprint
+### Error Code: SftpInvalidHostKeyFingerprint
 
 - **Message**: `Host key finger-print validation failed. Expected fingerprint is '<value in linked service>', real finger-print is '<server real value>'`