Technical Support
Resolving Mimecast Browser Isolation issues
If Great Space shows blank pages, unresponsive buttons, or repeated login prompts, your organisation's Mimecast email security may be opening the app inside a restricted “Secure Browser”. Here's how your IT team fixes it, permanently.
What's happening
Mimecast URL Protection rewrites links that arrive by email and can open them inside Browser Isolation — a sandboxed container that streams the page rather than running it in your own browser. Great Space relies on a live connection to Google Cloud services for real-time data sync, sign-in, and search, and those connections don't survive the container. The result looks like a broken app, but nothing is wrong with your account.
Symptoms you might see
- Pages load blank, or load once and then go white
- Buttons and menus do nothing when clicked
- You see 'time out' messages
- You are asked to sign in again every time you follow a link
- Uploads, live updates, or search results never finish loading
- The address bar shows a Mimecast address (e.g. protect-eu.mimecast.com) rather than app.greatspace.ai
Quick check for users
Before involving IT, open a new browser tab and type app.greatspace.ai directly rather than following a link from an email. If the app works that way, Mimecast link rewriting is the cause and the steps below will fix it for everyone.
It's also worth clearing your browser cache and signing in again — an isolated session can leave a stale one behind.
For your IT administrator
Adding Great Space to your Mimecast Managed URLs
Share these steps with your internal IT, security, or helpdesk team. They need Mimecast Administration Console access with permission to edit URL Protection policy.
- 1
Open Managed URLs
In the Mimecast Administration Console, go to Services › URL Protection › Managed URLs, then click Add Managed URL.
- 2
Permit greatspace.ai
Create the entry with these settings:
- Domain / URL: greatspace.ai
- Match Type: Domain — this covers every subdomain, including app.greatspace.ai
- Override Type: Permitted
- Disable Rewriting For This Entry: ticked — Mimecast then leaves our links untouched
- Disable User Awareness / Browser Isolation: ticked (or set to Disabled)
Click Save and Exit.
- 3
Permit the Google service dependencies
Great Space runs on Google Cloud infrastructure. If your Mimecast policies also inspect backend traffic, add an entry for each domain below — same steps, Match Type: Domain, Override Type: Permitted, rewriting disabled.
Domain What it's for Disable isolation greatspace.ai The Great Space website and application, including app.greatspace.ai and every other subdomain. Yes googleapis.com Google Cloud backend services that power sign-in, data sync, and search. Not required gstatic.com Static assets and security checks loaded by those Google services. Not required - 4
Wait for the policy to propagate
Mimecast policy changes typically take 15–30 minutes to reach every user. Once applied, ask affected users to clear their browser cache and open the link again.
Still seeing problems?
If your IT team has applied these exclusions and the app still misbehaves, email us at info@greatspace.ai with a screenshot of the full browser window, including the address bar. That tells us straight away whether the page is still being isolated. We typically reply within one working day.