diff --git a/src/main/java/eu/openaire/publications_retriever/util/file/FileUtils.java b/src/main/java/eu/openaire/publications_retriever/util/file/FileUtils.java
index 0794b08..83460d3 100644
--- a/src/main/java/eu/openaire/publications_retriever/util/file/FileUtils.java
+++ b/src/main/java/eu/openaire/publications_retriever/util/file/FileUtils.java
@@ -699,20 +699,19 @@ else if ( docFile.exists() )	// If it's not an already-known duplicate (this is
 
 	private static int getMaxStoringWaitingTime(int contentSize)
 	{
-		if ( contentSize != -2 ) {
-			if ( contentSize <= fiftyMBInBytes )
-				return 45_000;	// 45 seconds
-			else if ( contentSize <= oneHundredMBInBytes )
-				return 60_000;	// 1 min.
-			else if ( contentSize <= twoHundredMBInBytes )
-				return 120_000;	// 2 mins.
-			else if ( contentSize <= threeHundredMBInBytes )
-				return 180_000;	// 3 mins.
-			else
-				return 300_000;	// 5 mins.
-		}
-		else	// In case the server did not provide the "Content Length" header.
+		if ( contentSize == -2 )	// In case the server did not provide the "Content Length" header.
 			return 45_000;	// 45 seconds
+
+		if ( contentSize <= fiftyMBInBytes )
+			return 45_000;	// 45 seconds
+		else if ( contentSize <= oneHundredMBInBytes )
+			return 60_000;	// 1 min.
+		else if ( contentSize <= twoHundredMBInBytes )
+			return 120_000;	// 2 mins.
+		else if ( contentSize <= threeHundredMBInBytes )
+			return 180_000;	// 3 mins.
+		else
+			return 300_000;	// 5 mins.
 	}
 
 	
diff --git a/src/main/java/eu/openaire/publications_retriever/util/http/ConnSupportUtils.java b/src/main/java/eu/openaire/publications_retriever/util/http/ConnSupportUtils.java
index d83163b..5b9932a 100644
--- a/src/main/java/eu/openaire/publications_retriever/util/http/ConnSupportUtils.java
+++ b/src/main/java/eu/openaire/publications_retriever/util/http/ConnSupportUtils.java
@@ -89,7 +89,7 @@ public class ConnSupportUtils
 
 	public static final ConcurrentHashMap<String, DomainConnectionData> domainsWithConnectionData = new ConcurrentHashMap<>();
 
-	public static String userAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:130.0) Gecko/20100101 Firefox/130.0";	// This should not be "final", another program, using this software as a library, should be able to set its own "UserAgent".
+	public static String userAgent = "Mozilla/5.0 (Windows NT 10.0; Win64; x64; rv:133.0) Gecko/20100101 Firefox/133.0";	// This should not be "final", another program, using this software as a library, should be able to set its own "UserAgent".
 	public static String acceptLanguage = "en-US,en;q=0.5";
 
 
@@ -351,8 +351,8 @@ public static String getPlainMimeType(String mimeType)
 	 * @return
 	 * @throws FileNotRetrievedException
 	 */
-	public static DocFileData downloadAndStoreDocFile(HttpURLConnection conn, String id, String domainStr, String docUrl, boolean calledForPageUrl)
-			throws DocFileNotRetrievedException
+	public static FileData downloadAndStoreDocFile(HttpURLConnection conn, String id, String domainStr, String docUrl, boolean calledForPageUrl)
+			throws FileNotRetrievedException
 	{
 		boolean reconnected = false;
 		try {
@@ -387,9 +387,9 @@ public static DocFileData downloadAndStoreDocFile(HttpURLConnection conn, String
 				throw new FileNotRetrievedException(errMsg);
 			}
 
-				File docFile = docFileData.getDocFile();
-				try {	// In the "S3"-mode, we don't keep the files locally.
+			File docFile = fileData.getFile();
 			if ( ArgsUtils.shouldUploadFilesToS3 ) {
+				try {	// In the "S3"-mode, we don't keep the files locally, after they get transferred.
 					FileDeleteStrategy.FORCE.delete(docFile);    // We don't need the local file anymore..
 				} catch (Exception e) {
 					logger.warn("The file \"" + docFile.getName() + "\" could not be deleted after being uploaded to S3 ObjectStore!");
@@ -528,6 +528,12 @@ public static String onErrorStatusCode(String urlStr, String domainStr, int erro
 			if ( calledForPageUrl && (errorStatusCode != 404) && (errorStatusCode != 410) ) {
 				String errorText = getErrorMessageFromResponseBody(conn);
 				if ( errorText != null ) {
+
+					if ( domainStr.contains("doi.org") && errorText.contains("Not a DOI") ) {
+						logger.warn("Found a \"doi.org\" url with an invalid DOI: " + urlStr);
+						// In this case it is highly likely that the "DOI" in the url is a DOI-LINK.
+					}
+
 					errorLogMessage += " Error-text: " + errorText;
 					/*if ( errorStatusCode == 403 && errorText.toLowerCase().contains("javascript") ) {
 						// Use selenium to execute the JS.
diff --git a/src/main/resources/logback.xml b/src/main/resources/logback.xml
index 8348d7a..ff0cc00 100644
--- a/src/main/resources/logback.xml
+++ b/src/main/resources/logback.xml
@@ -28,6 +28,7 @@
     </appender>
 
     <logger name="crawlercommons" level="warn"/>
+    <logger name="eu.openaire.publications_retriever.crawler.MetadataHandler" level="debug"/>
 
     <root level="debug">
         <appender-ref ref="RollingFile" />