Dear Odoo community,
at the moment i'm trying to set up odoo for my little company. First of all, a few information about my setup
- Proxmox 7.3
- LXC Container with Debian 11 and installed docker
- Odoo 16 with PostgreSQL 15 database with docker compose behind Reverse Proxy Server (NPM)
- Own Domain with Subdomain linked to the Odoo docker instance --> "odoo.domain.com"

Odoo config file:
[options]
admin_passwd = ADMINPASSWORD
db_host = db
db_port = 5432
db_user = odoo
db_password = DBPASSWORD
db_name = odoo
list_db = False
smtp_server = mail.domain.com
smtp_user = mail@domain.com
smtp_password = MYPASSWORD
smtp_ssl = True
email_from = odoo@domain.com
smtp_port = 587
proxy_mode = True
workers = 0
timezone = Europe/Brussels

So far it seems to work quite well, but when i create and send offers and invoices via mail, i cannot use most of the functions that the mail would offer.
The customer gets a mail with my offer. Then normally the customer can add optional equipment, but when i press the button, nothing is happening. Same thing with the "Send Message" button, or the download button. Print is working as it should.
With invoices it's nearly the same, but there i even can't see the invoice in the browser, the circle is just spinning. Also i cannot use the function "Send message", or download. Pay now is also not working, i can open the windows, but i cannot select the pay method, so i'am not able to pay it. Hopefully someone can help me solving this problems.
If any more information is needed, may the docker compose file, i can post it, too.
Thank you guys in advance!

With kind regards,
Marc