# Virto Calendar App stuck on “Waiting for authorization”

Source: [https://docs.virtosoftware.com/docs/calendar-overlay-pro/administrators-guide-to-installation-and-configuration/troubleshooting-and-support/waiting-for-authorization/](https://docs.virtosoftware.com/docs/calendar-overlay-pro/administrators-guide-to-installation-and-configuration/troubleshooting-and-support/waiting-for-authorization/)
Product: Virto Calendar App
Updated: 2026-10-29


Every time Virto Calendar App opens, it signs you in to Microsoft 365 in the background. While it does so, the calendar area shows:

> Waiting for authorization

Normally this takes a second or two. If it stays on the screen, or is replaced by **Virto Calendar requires to be authorized** with an **Authorize** button, the browser has blocked the sign-in. The message under the heading says why.

## The messages and what to do

| What you see | Why | What to do |
|---|---|---|
| **Waiting for authorization** that does not go away | The background sign-in loads `https://calendar-app.virtosoftware.com` in a hidden frame and waits for its answer. The frame did not load or did not answer. | Open `https://calendar-app.virtosoftware.com` in a new browser tab. If it does not open, a proxy, firewall or security tool in your network blocks it: ask your IT team to allow the site. If it opens, reload the calendar page. If every user sees the message at the same time, see the last section below. |
| Login was blocked by popup blocker. Please add https://calendar-app.virtosoftware.com to allowed sites in Pop-up blocker settings of your Browser. | When the background sign-in fails on a SharePoint page or in Teams, the app opens a sign-in window. The browser blocked it. | Allow pop-ups for `https://calendar-app.virtosoftware.com`, reload the page and click **Authorize**. |
| Login was canceled by user. | The sign-in window was closed before the sign-in finished. | Click **Authorize** and complete the sign-in. |
| You must enable cookies (including third party cookies) to run the Calendar app. | Cookies are turned off in the browser. | Turn cookies on, including third-party cookies for the two sites above, and reload. |
| Login failed: followed by a code | Microsoft 365 refused the sign-in. | Note the code and send it with a screenshot to [support@virtosoftware.com](mailto:support@virtosoftware.com). |

## Users are asked to authorize every time

If the calendar asks people to click **Authorize** each time they open the page, the background sign-in is failing and the app falls back to the sign-in window. The background sign-in needs cookies from `calendar-app.virtosoftware.com` inside your SharePoint page or Teams tab, and browsers that block third-party cookies stop it. Allow third-party cookies for your SharePoint domain and `https://calendar-app.virtosoftware.com` on the users' computers, or through your browser policy for the whole organization:

- [Additional step for Chrome and Edge users](https://docs.virtosoftware.com/docs/calendar-overlay-pro/administrators-guide-to-installation-and-configuration/step-by-step-installation-instructions/additional-step-for-chrome-and-edge-users/index.md)
- [Additional step for Safari users](https://docs.virtosoftware.com/docs/calendar-overlay-pro/administrators-guide-to-installation-and-configuration/step-by-step-installation-instructions/additional-step-for-mac-users/index.md)

## Nobody in the organization can open the calendar

If the message appears for every user at the same moment, in every browser, the cause is unlikely to be the browsers. Check first that an administrator has granted the app's permissions: the app shows "Your global administrator has to consent to the required permissions on behalf of your organization." until this is done. See [Authorization & Permission Request](https://docs.virtosoftware.com/docs/calendar-overlay-pro/installation-and-configuration/authorization-and-permission-request/index.md) and, if the consent went wrong, [Resetting Authorization and Permissions](https://docs.virtosoftware.com/docs/calendar-overlay-pro/administrators-guide-to-installation-and-configuration/troubleshooting-and-support/resetting-authorization-and-permissions/index.md).

If the permissions are in place, write to [support@virtosoftware.com](mailto:support@virtosoftware.com) with the time it started and a screenshot.

## Related pages

- [Common Issues](https://docs.virtosoftware.com/docs/calendar-overlay-pro/administrators-guide-to-installation-and-configuration/troubleshooting-and-support/common-issues/index.md)
- [Virto Apps](https://docs.virtosoftware.com/docs/calendar-overlay-pro/installation-and-configuration/authorization-and-permission-request/virto-apps/index.md)