diff --git a/ReactNativeClient/lib/JoplinServerApi.ts b/ReactNativeClient/lib/JoplinServerApi.ts
index cb244a863..5c3c077aa 100644
--- a/ReactNativeClient/lib/JoplinServerApi.ts
+++ b/ReactNativeClient/lib/JoplinServerApi.ts
@@ -133,7 +133,11 @@ export default class JoplinServerApi {
 		const loadResponseJson = async () => {
 			if (!responseText) return null;
 			if (responseJson_) return responseJson_;
-			return JSON.parse(responseText);
+			try {
+				return JSON.parse(responseText);
+			} catch (error) {
+				throw new Error(`Cannot parse JSON: ${responseText.substr(0, 8192)}`);
+			}
 		};
 
 		const newError = (message:string, code:number = 0) => {
@@ -145,11 +149,13 @@ export default class JoplinServerApi {
 			try {
 				json = await loadResponseJson();
 			} catch (error) {
-				throw newError(`Unknown error: ${responseText.substr(0, 4096)}`, response.status);
+				throw newError(`Unknown error: ${responseText.substr(0, 8192)}`, response.status);
 			}
 
 			const trace = json.stacktrace ? `\n${json.stacktrace}` : '';
-			throw newError(json.error + trace, response.status);
+			let message = json.error;
+			if (!message) message = responseText.substr(0, 8192);
+			throw newError(message + trace, response.status);
 		}
 
 		const output = await loadResponseJson();
diff --git a/ReactNativeClient/lib/SyncTargetNextcloud.js b/ReactNativeClient/lib/SyncTargetNextcloud.js
index 2e01b4741..091261e9b 100644
--- a/ReactNativeClient/lib/SyncTargetNextcloud.js
+++ b/ReactNativeClient/lib/SyncTargetNextcloud.js
@@ -50,18 +50,22 @@ class SyncTargetNextcloud extends BaseSyncTarget {
 		return new Synchronizer(this.db(), await this.fileApi(), Setting.value('appType'));
 	}
 
-	async appApi() {
-		if (!this.appApi_) {
-			this.appApi_ = new JoplinServerApi({
-				baseUrl: () => JoplinServerApi.baseUrlFromNextcloudWebDavUrl(Setting.value('sync.5.path')),
-				username: () => Setting.value('sync.5.username'),
-				password: () => Setting.value('sync.5.password'),
-			});
+	async appApi(settings = null) {
+		const useCache = !settings;
 
-			this.appApi_.setLogger(this.logger());
-		}
+		if (this.appApi_ && useCache) return this.appApi_;
 
-		return this.appApi_;
+		const appApi = new JoplinServerApi({
+			baseUrl: () => JoplinServerApi.baseUrlFromNextcloudWebDavUrl(settings ? settings['sync.5.path'] : Setting.value('sync.5.path')),
+			username: () => settings ? settings['sync.5.username'] : Setting.value('sync.5.username'),
+			password: () => settings ? settings['sync.5.password'] : Setting.value('sync.5.password'),
+		});
+
+		appApi.setLogger(this.logger());
+
+		if (useCache) this.appApi_ = appApi;
+
+		return appApi;
 	}
 
 }
diff --git a/ReactNativeClient/lib/components/shared/config-shared.js b/ReactNativeClient/lib/components/shared/config-shared.js
index 15f7cbc17..a1fd856a2 100644
--- a/ReactNativeClient/lib/components/shared/config-shared.js
+++ b/ReactNativeClient/lib/components/shared/config-shared.js
@@ -59,7 +59,7 @@ shared.checkNextcloudApp = async function(comp, settings) {
 
 	comp.setState({ checkNextcloudAppResult: 'checking' });
 	let result = null;
-	const appApi = await reg.syncTargetNextcloud().appApi();
+	const appApi = await reg.syncTargetNextcloud().appApi(settings);
 
 	try {
 		result = await appApi.setupSyncTarget(settings['sync.5.path']);
@@ -79,14 +79,16 @@ shared.checkNextcloudApp = async function(comp, settings) {
 };
 
 shared.updateSettingValue = function(comp, key, value) {
-	const settings = Object.assign({}, comp.state.settings);
-	const changedSettingKeys = comp.state.changedSettingKeys.slice();
-	settings[key] = Setting.formatValue(key, value);
-	if (changedSettingKeys.indexOf(key) < 0) changedSettingKeys.push(key);
+	comp.setState(state => {
+		const settings = Object.assign({}, state.settings);
+		const changedSettingKeys = state.changedSettingKeys.slice();
+		settings[key] = Setting.formatValue(key, value);
+		if (changedSettingKeys.indexOf(key) < 0) changedSettingKeys.push(key);
 
-	comp.setState({
-		settings: settings,
-		changedSettingKeys: changedSettingKeys,
+		return {
+			settings: settings,
+			changedSettingKeys: changedSettingKeys,
+		};
 	});
 };