Cant access WebDav over HTTPS

[bluebell]

Can someone please explain exactly how to use WebDav over HTTPS?

I can access the WebDav server over HTTP... my specific use case, is using duckdns.org and Solid Explorer on Android. I select HTTP, the duckdns domain, default WebDav port 9900 (which I also have forwarded on my router, although I haven't tested without the forwarding). This works perfectly fine but am concerned about the security and want to use the HTTPS option in Solid Explorer.

Upon attempting the same method with the SSL default port of 474 for HTTPS, Solid Explorer returns "Solid Explorer attempted to explore an invalid operation".
The still occurs when I go to the SSL Store on TOS and download the terra-master.com certificate, and install that on my phone.
I also downloaded and installed the same certificate to my laptop, as well as the *.tnas.link certificate and attempted to browse to "https://192.168.1.152:474". I was given a warning saying the connection is not private and the ip is not trusted in the certificate store... I continued through this and got to a page that only displayed the #recycle/ path as I wasn't able to log in, but the HTTPS is not secure...

In short... I've no idea what I'm doing and why this is so difficult to work... please help with this.
If I can at least get HTTPS working on my PC, I can work on my own to get it working on Solid Explorer.

Thanks.

[TMSupport]

Please advise your TNAS model number and current TOS version.
HTTPS access of WebDAV is only supported in TOS4.2.11, while it may be not stable yet.

[bluebell]

Thanks for the quick reply.

My TNAS is the F2-210, running TOS 4.2.08-2101111540, with no update available when I check...
If 4.2.11 is required, that will explain it.

I managed to view my files on my browser through https://192.168.1.152:474 after installing the certificates like i mentioned in the initial post, however i get the error "The certificate for this site is not valid"

Its starting to seem like this is a separate issue to Solid Explorer and using HTTPS WebDav. Am i correct in saying that Solid Explorer is not working because there is no HTTPS WebDav protocol in my TOS version... and while im able to access my files locally on the address mentioned above on my laptop, that isnt actually using the WebDav protocol (just a SSL port), and instead just running into certificate errors?

[TMSupport]

TOS4.2.11 for ARM model is not available at the moment.

[bluebell]

Is there a time frame at all on when TOS 4.2.11 will come to ARM devices like my F2-210?

[TMSupport]

We will have vacation here from May 1 to May 5, the new TOS version of ARM model is estimated to be released one week later after the vacation.

[bluebell]

Perfect. Thank you for your information
I look forward to the new update