Nextcloud v28.0.3 rejects DAVx5 handshake

I am running the latest version of Nextcloud on my file server PC with Ubuntu Server 22.04.4 OS installed. It is a direct to metal script installation of Nextcloud . In other words, it is not a SNAP or a Docker Portainer installation. Below is the link to the installation script I used:

https://github.com/nicrame/Linux-Scripts/blob/master/nextcloud-ins.sh

Previously I was running Nextcloud v26 and my Davx5 app worked perfectly. Any change I made on my Android phone’s Calendar or Contacts app would automatically be synced to the Calendar and Contacts app on my Nextcloud v26 installation. However, after upgrading to Nextcloud v28.0.3 my Davx5 app no longer works to the point where I cannot even create a new Account because the error shown below prevents it:

Configuration Detection: Couldn't find Caldav or Carddav service

It appears as a popup window within the “Add Account” screen in my Davx5 app on my phone. In short, I believe Nextcloud v28.0.3 is blocking my Davx5 app to successfully handshake and establish a connection. This was not the case on my Nextcloud v26 installation.

I have confirmed my Nextcloud v28.0.3 installation does not have 2Factor Authentication enabled and beyond that there is no other troubleshooting I can think of performing. Therefore, I would really appreciate it a lot if anybody in this forum can offer any other troubleshooting ideas I could try out.

To duplicate the error, I am selecting the “Login with URL and user name” option found in the “Add Account” Davx5 screen to create a Davx5 account. Below is the BASE URL format I am using which is the same one that worked on the Nextcloud v26 installation but no longer works in the Nextcloud v28.0.3 installation. I then selected the “Login” button and a window appears with the error shown above.

https://123.456.7.899/remote.php/dav

Is the BASE URL format I am using shown above correct? Or is there another BASE URL format I should be using?

Below are the 5 options DAVx5 offers to add an account. I am using the second one from the top. I tried using the Nextcloud option but that requires I have my Nextcloud setup as a website with a domain.com URL which is not the case for my Nextcloud setup. Any advice on what other options I should try is welcome.

Lastly, below are a couple of links I have referred to for help and have not solved my problem:

https://www.davx5.com/tested-with/nextcloud

https://support.kerioconnect.gfi.com/hc/en-us/articles/360017061019-Configuring-CalDAV-CardDAV-accounts-via-DAVx5-in-Android-devices

Any advice will be tremendously welcome because I have hit a brick wall with this problem. Thank you for your time.

Was it working when you have been on NC 27? If I upgrade through a version in NC, I usually connect to the intermediate, make sure all the apps are more or less running and there are no strange errors, and I do all the new recommendation when you go on the admin interface (adding db indices etc.).

The base URL usually is just the domain name (or everything before /remote.php) like in the links you have put in the end. In your case https://123.456.7.899
The correct calendar and contact URLs are retrieved by the service discovery:
General troubleshooting — Nextcloud latest Administration Manual latest documentation
(if you go on the admin interface, I think it tries to check for them automatically).

For that also check the webserver configuration with the samples in the documentation (especially for nginx), these can change a bit between versions.