diff --git a/lib/KOReaderSync/KOReaderSyncClient.cpp b/lib/KOReaderSync/KOReaderSyncClient.cpp
index c5053c64..f0183452 100644
--- a/lib/KOReaderSync/KOReaderSyncClient.cpp
+++ b/lib/KOReaderSync/KOReaderSyncClient.cpp
@@ -19,6 +19,10 @@ void addAuthHeaders(HTTPClient& http) {
   http.addHeader("Accept", "application/vnd.koreader.v1+json");
   http.addHeader("x-auth-user", KOREADER_STORE.getUsername().c_str());
   http.addHeader("x-auth-key", KOREADER_STORE.getMd5Password().c_str());
+
+  // HTTP Basic Auth (RFC 7617) header. This is needed to support koreader sync server embedded in Calibre Web Automated
+  // (https://github.com/crocodilestick/Calibre-Web-Automated/blob/main/cps/progress_syncing/protocols/kosync.py)
+  http.setAuthorization(KOREADER_STORE.getUsername().c_str(), KOREADER_STORE.getPassword().c_str());
 }
 
 bool isHttpsUrl(const std::string& url) { return url.rfind("https://", 0) == 0; }