SSL certificate brokes work

I installed Akaunting at Digital Ocean after adding SSL certificate there were happened a lot of issues:
- no ability to delete invoice
- no ability to create new item thought editing invoice
- no ability to install additional app

It looks like I push the button and nothing happened. Also browser says that: "Some parts of this page are not secure, such as images.” What counts as insecure?
How to resolve?
Thank you for help

You can set the domain in ".env" file like the following:

APP_URL=https://my-akaunting.com