diff --git a/src/delete-caldav-object.c b/src/delete-caldav-object.c
index 9a85168..3e5c078 100644
--- a/src/delete-caldav-object.c
+++ b/src/delete-caldav-object.c
@@ -235,13 +235,16 @@ gboolean caldav_delete(caldav_settings* settings, caldav_error* error) {
 					 * hoping for the best.
 					 */
 					else if (lock_error.code == 501) {
-						lock_token = g_strdup("");
+						lock_error.code = 0;
+						g_free(lock_error.str);
+						lock_error.str = NULL;
+						LOCKSUPPORT = FALSE;
 					}
 					else {
 						lock = -1;
 					}
 				}
-				if (! LOCKSUPPORT || (LOCKSUPPORT && lock_token && lock_error.code != 423)) {
+				if (lock == 0) {
 					curl_easy_setopt(curl, CURLOPT_HTTPHEADER, http_header);
 					curl_easy_setopt(curl, CURLOPT_URL, rebuild_url(settings, url));
 					curl_easy_setopt(curl, CURLOPT_POSTFIELDS, NULL);
@@ -251,7 +254,7 @@ gboolean caldav_delete(caldav_settings* settings, caldav_error* error) {
 					curl_easy_setopt(curl, CURLOPT_UNRESTRICTED_AUTH, 1);
 					curl_easy_setopt(curl, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
 					res = curl_easy_perform(curl);
-					if (LOCKSUPPORT && lock_token) {
+					if (LOCKSUPPORT) {
 						caldav_unlock_object(
 								lock_token, url, settings, &lock_error);
 					}
@@ -465,13 +468,16 @@ gboolean caldav_tasks_delete(caldav_settings* settings, caldav_error* error) {
 					 * hoping for the best.
 					 */
 					else if (lock_error.code == 501) {
-						lock_token = g_strdup("");
+						lock_error.code = 0;
+						g_free(lock_error.str);
+						lock_error.str = NULL;
+						LOCKSUPPORT = FALSE;
 					}
 					else {
 						lock = -1;
 					}
 				}
-				if (! LOCKSUPPORT || (LOCKSUPPORT && lock_token && lock_error.code != 423)) {
+				if (lock == 0) {
 					curl_easy_setopt(curl, CURLOPT_HTTPHEADER, http_header);
 					curl_easy_setopt(curl, CURLOPT_URL, rebuild_url(settings, url));
 					curl_easy_setopt(curl, CURLOPT_POSTFIELDS, NULL);
@@ -481,7 +487,7 @@ gboolean caldav_tasks_delete(caldav_settings* settings, caldav_error* error) {
 					curl_easy_setopt(curl, CURLOPT_UNRESTRICTED_AUTH, 1);
 					curl_easy_setopt(curl, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
 					res = curl_easy_perform(curl);
-					if (LOCKSUPPORT && lock_token) {
+					if (LOCKSUPPORT) {
 						caldav_unlock_object(
 								lock_token, url, settings, &lock_error);
 					}
diff --git a/src/modify-caldav-object.c b/src/modify-caldav-object.c
index fb3a4d0..3db1e59 100644
--- a/src/modify-caldav-object.c
+++ b/src/modify-caldav-object.c
@@ -235,13 +235,16 @@ gboolean caldav_modify(caldav_settings* settings, caldav_error* error) {
 						 * hoping for the best.
 						 */
 						else if (lock_error.code == 501) {
-							lock_token = g_strdup("");
+							lock_error.code = 0;
+							g_free(lock_error.str);
+							lock_error.str = NULL;
+							LOCKSUPPORT = FALSE;
 						}
 						else {
 							lock = -1;
 						}
 					}
-					if (! LOCKSUPPORT || (LOCKSUPPORT && lock_token && lock_error.code != 423)) {
+					if (lock == 0) {
 						curl_easy_setopt(curl, CURLOPT_HTTPHEADER, http_header);
 						curl_easy_setopt(curl, CURLOPT_URL, rebuild_url(settings, url));
 						curl_easy_setopt(curl, CURLOPT_POSTFIELDS, settings->file);
@@ -252,7 +255,7 @@ gboolean caldav_modify(caldav_settings* settings, caldav_error* error) {
 						curl_easy_setopt(curl, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
 						curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "PUT");
 						res = curl_easy_perform(curl);
-						if (LOCKSUPPORT && lock_token) {
+						if (LOCKSUPPORT) {
 							caldav_unlock_object(
 									lock_token, url, settings, &lock_error);
 						}
@@ -475,13 +478,13 @@ gboolean caldav_tasks_modify(caldav_settings* settings, caldav_error* error) {
 						 * hoping for the best.
 						 */
 						else if (lock_error.code == 501) {
-							lock_token = g_strdup("");
+							LOCKSUPPORT = FALSE;
 						}
 						else {
 							lock = -1;
 						}
 					}
-					if (! LOCKSUPPORT || (LOCKSUPPORT && lock_token && lock_error.code != 423)) {
+					if (lock == 0) {
 						curl_easy_setopt(curl, CURLOPT_HTTPHEADER, http_header);
 						curl_easy_setopt(curl, CURLOPT_URL, rebuild_url(settings, url));
 						curl_easy_setopt(curl, CURLOPT_POSTFIELDS, settings->file);
@@ -492,7 +495,7 @@ gboolean caldav_tasks_modify(caldav_settings* settings, caldav_error* error) {
 						curl_easy_setopt(curl, CURLOPT_POSTREDIR, CURL_REDIR_POST_ALL);
 						curl_easy_setopt(curl, CURLOPT_CUSTOMREQUEST, "PUT");
 						res = curl_easy_perform(curl);
-						if (LOCKSUPPORT && lock_token) {
+						if (LOCKSUPPORT) {
 							caldav_unlock_object(
 									lock_token, url, settings, &lock_error);
 						}