WebDAV with HTTPS not working

[Tharadash]

When trying to connect to a IPv4 HTTPS WebDAV instance (on a Synology NAS on default port 5006 in my case), even with an imported self signed certificate, the OnlyOffice Documents App is not able to open a connection.
With the same IP and username/password combo, HTTP on port 5005 works fine as expected.
The attached logcat shows logs of both connections - I hope there's enough data in there to see the issue (I myself can't make heads or tails of it):
logcat.txt

Device: Fairphone 3+
Android version: 13
Kernel: 4.9.337-perf+
App source: Google Play Store
App version: 8.2.3

[Andrew-Dudov]

Hello @Tharadash We do not work with self-signed certificates.

[Tharadash]

Thanks for your quick reply @Andrew-Dudov!
I understand your reasoning, however this makes it insecure (by relying on unencrypted HTTP) connecting to local-network-only WebDAV storages for users without an own domain and SSL certificates.
My use case is using OnlyOffice Documents to connect to my private Synology-NAS' WebDAV server - which is neither in a domain nor has a "valid" SSL certificate since I access my network through VPN only.

Would it thus be possible to:
a) provide a more meaningful error message - e. g. "SSL certificate can't be validated"?
b) add a checkbox to optionally disable certificate validation - e. g. "[ ] Skip SSL certificate validation"?

[Andrew-Dudov]

@Tharadash
I will answer in order:
a) I confirm you problem. I have issued this enchancement 72567
b) I ask you to open a separate issue on this point

[Tharadash]

@Andrew-Dudov thank you!
I just opened #370 as you requested.