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Adding custom DAV calendar subscription opens Google login - Can't subscribe

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  • 1 has this problem
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  • Last reply by ffacc

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I have a custom Nextcloud server setup with DAV calendars. With the new Thunderbird 91, whenever I try to add the new calendar, a modal with the Google sign-in page appears. I close that, enter the password in the next pop-up, and the calendar is eventually listed, but nothing gets synced. If I try to create an event, an error is shown saying that the calendar might be read-only , and it gets marked RO after that.

I tried to create a fictious email account having the same domain (@xyz.com) as my NC calendar, and to my surprise it detected it as a Google email server (supposedly GSuite) based on ISP DB, although there are no email services running on it and the ports are closed.

So the question is, why does TB detect custom DAV calendars as Google's and opens the login modal? Is there any way to turn off this detection for calendars? Any workaround for this issue?

I have a custom Nextcloud server setup with DAV calendars. With the new Thunderbird 91, whenever I try to add the new calendar, a modal with the Google sign-in page appears. I close that, enter the password in the next pop-up, and the calendar is eventually listed, but nothing gets synced. If I try to create an event, an error is shown saying that the calendar might be read-only , and it gets marked RO after that. I tried to create a fictious email account having the same domain (@xyz.com) as my NC calendar, and to my surprise it detected it as a Google email server (supposedly GSuite) based on ISP DB, although there are no email services running on it and the ports are closed. So the question is, why does TB detect custom DAV calendars as Google's and opens the login modal? Is there any way to turn off this detection for calendars? Any workaround for this issue?

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To add to it, things work fine on TB 78 and other clients.

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So who does host the dav server?

My understanding of the process is requests are made to the URL entered and when a suitable challenge is received from the server a suitable authentication request is displayed. The preferred authentication is oAuth if available and what is displayed in those authentication dialogs is fed out by the authentication server, not Thunderbird. If the authentication method is just a password, then a username password dialog is shown.

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It's hosted on some cloud provider (vultr) and not GCP.

Can I ask what that challenge is and how it is determined (for DAV)? In the case of my Nextcloud instance, there is no dependency on Google or 3rd-party login for OAuth, and it should show the username password dialog as it has until v78. Even if it was OAuth-based, it should show my Nextcloud instance's login page. Don't know why it's showing Google's...