Admin panel doesnt work

Expected Behaviour:

A password prompt opens up, like the installer says

Actual Behaviour:

Displays the following in plain text:

Total queries (- clients)

Queries Blocked

Percentage Blocked

Domains on Blocklist

Total queries over last hours
Client activity over last hours
Query Types
Upstream servers
Top Permitted Domains
Domain Hits Frequency
Top Blocked Domains
Domain Hits Frequency
Top Clients (total)
Client Requests Frequency
Top Clients (blocked only)
Client Requests Frequency

Debug Token:

https://tricorder.pi-hole.net/drG9OknA/

[80] is in use by apache2 (https://docs.pi-hole.net/main/prerequisites/#ports)

The Pi-hole web server (lighttpd) cannot bind to port 80 because Apache2 is already on that port.

Can I assign it to another port? I know I will have to append :[port] to the end of the address.

A permanent way to change the lighttpd port is: