Website stopped working after updating from Joomla 4 to 5

Hi,
I performed an update from Joomla 4 to 5 but now after clicking a link on the website, the website freezes and I see the following error in Chrome console:
"Uncaught ReferenceError: Joomla is not defined"

Website: zahnarztpraxis-koenigstein.de/

I did not update the template as I don't have an update file.
Can you please help?
Thanks,
Robin

Hello,

You must have an active membership account to get support.

Regards,
Milos

Ok, renewed.

Hello,

When I try to access your website, it's not working at all. I get this error:
Please check if the URL provided is correct. You will need to restore your website from backups if it's damaged during the Joomla upgrade.

This is the procedure to upgrade website from Joomla 4 to 5:

First of all, make a full website backup.

Then you can proceed with the upgrade. If you are happy with the results and the site is working fine, you are done.

If you notice some problems, you should re-install the template after the Joomla upgrade using the standard template installation method (install the file hot_coworking5x.zip). After that, go to the template settings and save it once (you don't need to change anything).

If anything goes wrong, you will have to restore the website from backup. In this case, please keep in mind that some 3rd party extensions (especially plugins) that you have installed can break the upgrade process or make it impossible (until they are uninstalled).

Regards,
Milos

Hi Milos,
thanks for the support. I provided the link that should forward to https://www.xn--zahnarztpraxis-knigstein-0oc.de/
Please check that one.
Of course I have an backup but I also need to update to v5. So what is the best way of doing it? Installing your template file after the update or before?
Thanks,
Robin

Hello,

The link you provided now works fine. I don't see any Joomla errors.

You should upgrade Joomla 4 to 5 first, and then install the template file hot_clinic5x.zip), go to template parameters, and save once (you don't need to change anything).

IMPORTANT: Check for errors and notifications during the upgrade. Joomla will list all extensions (plugins) that are not compatible, so you should disable them before upgrading.

Regards,
Milos