Registration for custom homeserver works on app.element.io but not the Android app

### Steps to reproduce

1. I confirmed that I can register new accounts on my custom homeserver from app.element.io.
2. Then I tried the same from the Android app.
3. I replaced "matrix.org" with my homeserver URL ("matrix.example.com", the same one I used on app.element.io).
4. I get a pop-up saying "The application is not able to create an account on this homeserver. Do you want to signup using a web client?"
5. I select "yes".
6. I am sent to a browser with the URL "http://matrix.example.com/_matrix/static/client/register" and the response is:

```json
{"errcode":"M_UNRECOGNIZED","error":"M_UNRECOGNIZED: Not Found"}
```

To be clear, I'm not certain that URL is actually what's being requested, because the URL bar is truncated and only shows: "http://matrix.example.com/_matrix/static/client/registe...". I'm not able to interact with this browser in any way to get the complete URL. I can't even rotate my phone to get a landscape UI.

### Outcome

#### What did you expect?

I expected to be able to successfully register a new account.

#### What happened instead?

Failure.

### Your phone model

Google Pixel 7

### Operating system version

Android 14

### Application version and app store

1.6.22 from Play Store

### Homeserver

conduwuit 0.4.6

### Will you send logs?

No

### Are you willing to provide a PR?

Yes