I’m on the same version and had the same issue. This is a bug in my eyes. To resolve this I edited the /vendor/livewire/livewire/config/livewire.php file. Edit the lines that contain asset url and app url to your domain url. Syntax should be “https://www.yourdomain.com” with the quotes. Save it. Go back to your ninja root directory and issue the following command: sudo php artisan livewire:publish and test the client portal. This forces livewire to use the correct url.
From a bug perspective: livewire should be taking whatever the defined url was issued at the setup of InvoiceNinja. This goes for any url the app needs to function. I know it works fine out of the box as a root app for the webserver and issues as a subfolder for the app. I run my as a subfolder and had to make these changes for it to work properly. Either either way hopefully this gets addressed in future upgrades to the software.