What you’re seeing
- An outside partner sees "AADSTS90072: User account from identity provider does not exist in tenant and cannot access the application".
- A contractor clicks a shared Teams or SharePoint link and is stopped at the Microsoft sign-in page.
- The guest is signed in with a different work or personal account than the one the invitation was sent to.
- Inviting the same person again appears to succeed, but the error keeps returning.
Common causes
Every environment is different, but these are the causes our engineers find most often:
- The guest never redeemed the invitation, so no guest account exists yet in your directory.
- The partner is signing in with a different email address or Microsoft account than the one that was invited.
- The guest's browser is already signed in to their own organization, and that session is offered instead of the invited identity.
- External collaboration settings or cross-tenant access policies block users from the partner's organization.
- The guest account was deleted or expired during an access review or cleanup.
Why it matters
Small businesses increasingly share files and Teams channels with accountants, contractors and suppliers. When a partner cannot get in, projects stall, documents get emailed around as attachments, and sensitive files drift outside the controls you set up. Each failed attempt also burns goodwill with clients who see your firm as hard to work with, and teams often respond by sharing anonymous links that anyone can open.
How AskTechGurus fixes it
Skip the trial and error. A certified engineer works on your actual system, finds the root cause, and fixes it properly.
Tell us what’s happening
Submit a ticket in about two minutes. Paste the error, describe what changed, and pick your tier. No charge to submit.
A certified engineer diagnoses it
A vetted, US-based systems engineer claims your ticket, usually within minutes during business hours, and investigates over a secure remote session you can watch and end at any time.
Fixed and verified with you
The engineer resolves the root cause and confirms with you that it’s working. You don’t just get a workaround, and you get a plain-English summary of what was wrong.
Pay only when it’s resolved
Fixed price from $99, invoiced only after you approve the fix. If it isn’t resolved, you don’t pay.
Frequently asked questions
We invited them. Why doesn't their account exist?
An invitation only becomes a working guest account once it is redeemed with the exact identity it was sent to. Signing in with another account produces AADSTS90072.
Is it risky to give partners guest access?
Guest access is safer than emailing files or using open share links, provided it is reviewed and removed when the work ends.
Can you help us set up partner access properly?
Yes. A certified US engineer can work through it with you in a remote secure session, from $99, and you only pay once partners can sign in.