diff --git a/package.json b/package.json
index 81b4c3bb62..0e7bf58327 100644
--- a/package.json
+++ b/package.json
@@ -421,6 +421,7 @@
   "devDependencies": {
     "@types/chai": "^4.1.4",
     "@types/debounce": "^3.0.0",
+    "@types/graphql": "^14.0.5",
     "@types/keytar": "^4.0.1",
     "@types/lodash": "^4.14.106",
     "@types/markdown-it": "^0.0.5",
diff --git a/src/github/credentials.ts b/src/github/credentials.ts
index b34d38c1ed..cd0c133c62 100644
--- a/src/github/credentials.ts
+++ b/src/github/credentials.ts
@@ -4,7 +4,7 @@
  *--------------------------------------------------------------------------------------------*/
 
 import * as Octokit from '@octokit/rest';
-import { ApolloClient, InMemoryCache, NormalizedCacheObject } from 'apollo-boost';
+import { ApolloClient, InMemoryCache, NormalizedCacheObject, gql } from 'apollo-boost';
 import { setContext } from 'apollo-link-context';
 import * as vscode from 'vscode';
 import { agent } from '../common/net';
@@ -25,7 +25,7 @@ const AUTH_INPUT_TOKEN_CMD = 'auth.inputTokenCallback';
 
 export interface GitHub {
 	octokit: Octokit;
-	graphql: ApolloClient<NormalizedCacheObject>;
+	graphql: ApolloClient<NormalizedCacheObject> | null;
 }
 
 export class CredentialStore {
@@ -74,7 +74,7 @@ export class CredentialStore {
 
 		if (token) {
 			if (await server.validate(token)) {
-				octokit = this.createHub({ host, token });
+				octokit = await this.createHub({ host, token });
 			} else {
 				Logger.debug(`Token is no longer valid for host ${host}.`, 'Authentication');
 			}
@@ -137,7 +137,7 @@ export class CredentialStore {
 				this.willStartLogin(authority);
 				const login = await server.login();
 				if (login && login.token) {
-					octokit = this.createHub(login);
+					octokit = await this.createHub(login);
 					await setToken(login.host, login.token, { emit: false });
 					vscode.window.showInformationMessage(`You are now signed in to ${authority}`);
 				}
@@ -174,7 +174,7 @@ export class CredentialStore {
 		return octokit && (octokit as any).currentUser && (octokit as any).currentUser.login === username;
 	}
 
-	private createHub(creds: IHostConfiguration): GitHub {
+	private async createHub(creds: IHostConfiguration): Promise<GitHub> {
 		const baseUrl = `${HostHelper.getApiHost(creds).toString().slice(0, -1)}${HostHelper.getApiPath(creds, '')}`;
 		let octokit = new Octokit({
 			agent,
@@ -187,17 +187,30 @@ export class CredentialStore {
 			token: creds.token || '',
 		});
 
-		return {
-			octokit,
-			graphql: new ApolloClient({
-				link: link(baseUrl, creds.token || ''),
-				cache: new InMemoryCache,
-				defaultOptions: {
-					query: {
-						fetchPolicy: 'no-cache'
-					}
+		const graphql = new ApolloClient({
+			link: link(baseUrl, creds.token || ''),
+			cache: new InMemoryCache,
+			defaultOptions: {
+				query: {
+					fetchPolicy: 'no-cache'
 				}
+			}
+		});
+
+		let supportsGraphQL = true;
+		await graphql.query({ query: gql `query { viewer { login } }` })
+			.then(result => {
+				Logger.appendLine(`${baseUrl}: GraphQL support detected`);
+				Logger.appendLine(JSON.stringify(result, null, 2));
 			})
+			.catch(err => {
+				Logger.appendLine(`${baseUrl}: GraphQL not supported (${err.message})`);
+				supportsGraphQL = false;
+			});
+
+		return {
+			octokit,
+			graphql: supportsGraphQL ? graphql : null,
 		};
 	}
 
diff --git a/src/github/githubRepository.ts b/src/github/githubRepository.ts
index 324fec5301..a7321df251 100644
--- a/src/github/githubRepository.ts
+++ b/src/github/githubRepository.ts
@@ -53,7 +53,7 @@ export class GitHubRepository implements IGitHubRepository, vscode.Disposable {
 			}
 
 			await this.ensure();
-			this.commentsProvider = this.supportsGraphQl() ? new PRDocumentCommentProviderGraphQL() : new PRDocumentCommentProvider();
+			this.commentsProvider = this.supportsGraphQl ? new PRDocumentCommentProviderGraphQL() : new PRDocumentCommentProvider();
 			this._toDispose.push(vscode.workspace.registerDocumentCommentProvider(this.commentsProvider));
 		} catch (e) {
 			console.log(e);
@@ -72,7 +72,7 @@ export class GitHubRepository implements IGitHubRepository, vscode.Disposable {
 	constructor(public remote: Remote, private readonly _credentialStore: CredentialStore) {
 	}
 
-	supportsGraphQl(): boolean {
+	get supportsGraphQl(): boolean {
 		return !!(this.hub && this.hub.graphql);
 	}
 
@@ -279,7 +279,7 @@ export class GitHubRepository implements IGitHubRepository, vscode.Disposable {
 	async getPullRequest(id: number): Promise<PullRequestModel | undefined> {
 		try {
 			Logger.debug(`Fetch pull request ${id} - enter`, GitHubRepository.ID);
-			const { octokit, query, remote } = await this.ensure();
+			const { octokit, query, remote, supportsGraphQl } = await this.ensure();
 			let prsResult = await octokit.pullRequests.get({
 				owner: remote.owner,
 				repo: remote.repositoryName,
@@ -292,7 +292,7 @@ export class GitHubRepository implements IGitHubRepository, vscode.Disposable {
 				return;
 			}
 
-			if (this.supportsGraphQl()) {
+			if (supportsGraphQl) {
 				const { data } = await query<PullRequestResponse>({
 					query: queries.PullRequest,
 					variables: {
diff --git a/src/github/pullRequestManager.ts b/src/github/pullRequestManager.ts
index 3e3ed9684e..727bd24c16 100644
--- a/src/github/pullRequestManager.ts
+++ b/src/github/pullRequestManager.ts
@@ -666,10 +666,10 @@ export class PullRequestManager {
 
 	async getTimelineEvents(pullRequest: PullRequestModel): Promise<TimelineEvent[]> {
 		Logger.debug(`Fetch timeline events of PR #${pullRequest.prNumber} - enter`, PullRequestManager.ID);
-		const { octokit, query, remote } = await pullRequest.githubRepository.ensure();
+		const { octokit, query, remote, supportsGraphQl } = await pullRequest.githubRepository.ensure();
 
 		let ret = [];
-		if (pullRequest.githubRepository.supportsGraphQl()) {
+		if (supportsGraphQl) {
 			try {
 				const { data } = await query<TimelineEventsResponse>({
 					query: queries.TimelineEvents,
@@ -794,7 +794,7 @@ export class PullRequestManager {
 			return undefined;
 		}
 
-		if (!pullRequest.githubRepository.supportsGraphQl()) {
+		if (!pullRequest.githubRepository.supportsGraphQl) {
 			return;
 		}
 
diff --git a/src/github/pullRequestOverview.ts b/src/github/pullRequestOverview.ts
index 0c0757d313..c8a068adaa 100644
--- a/src/github/pullRequestOverview.ts
+++ b/src/github/pullRequestOverview.ts
@@ -163,7 +163,7 @@ export class PullRequestOverviewPanel {
 			const isCurrentlyCheckedOut = pullRequestModel.equals(this._pullRequestManager.activePullRequest);
 			const canEdit = this._pullRequestManager.canEditPullRequest(this._pullRequest);
 			const defaultMergeMethod = vscode.workspace.getConfiguration('githubPullRequests').get<string>('defaultMergeMethod');
-			const supportsGraphQl = pullRequestModel.githubRepository.supportsGraphQl();
+			const supportsGraphQl = pullRequestModel.githubRepository.supportsGraphQl;
 
 			this._postMessage({
 				command: 'pr.initialize',
diff --git a/src/view/reviewManager.ts b/src/view/reviewManager.ts
index 1d6856a0fc..77dacd2fac 100644
--- a/src/view/reviewManager.ts
+++ b/src/view/reviewManager.ts
@@ -900,7 +900,7 @@ export class ReviewManager implements vscode.DecorationProvider {
 	}
 
 	private registerCommentProvider() {
-		const supportsGraphQL = this._prManager.activePullRequest && (this._prManager.activePullRequest as PullRequestModel).githubRepository.supportsGraphQl();
+		const supportsGraphQL = this._prManager.activePullRequest && (this._prManager.activePullRequest as PullRequestModel).githubRepository.supportsGraphQl;
 		if (supportsGraphQL) {
 			this._localToDispose.push(onDidSubmitReview(submittedComments => {
 				this.updateCommentPendingState(submittedComments);