OK, the problem is solved.
If I set the proxy in the Wifi connection, Android says that the connection is limited. As soon as you put the same proxy but in transparent mode (not set in Android, but filter correctely by the router when Android try to connect to outside), the connection is fully established and the synchronization is immediately done.
Sorry for the noise.
I would appreciate if one day, you may remove the needed support to Android sync…
Thanks a lot

@esmuellerthier Sorry, I mean with the browser on the mobile device, not on your PC or elsewhere.

DAVx5 is blocked access to the given host/port and so the connection times out. There’s nothing DAVx5 can do against that.

So it’s solved for you? Fine, I’ll set the topic to resolved.

Maybe supporting local syncs without Internet will be possible with DAVx5 some day (I’d love to see that). But first there are many things to do

Hi
Many thanks for your reply! I tested that and I found that I actually couldn’t access it (no IP address) from my Android browser which is strange because anywhere else (home PC, Laptop, PC at work, Thunderbird…) I’ve always had access.
So I looked up the NAS’s IP address on my modem and when I use the IP itself in DAVx5 it worked!! So I assume this has something to do with static/dynamic IP addresses, what do you think? I assumed my NAS has a static address because I can always login with the same address (monolith:5000) but I guess I was just lucky that when I updated it, it received the same address after restart. I bought it half a year ago…
So long story short, I’ll have to make sure that this address is static and it will keep on working/synchronizing or do you think the problem lies somewhere else?
Your help is highly appreciated, thanks again!

@rfc2822

What about giving Internet access to your device and using a firewall to restrict traffic?

My local network is entirely airgapped with no external internet access, and that’s the way it has to be. My tablet is never going to touch the internet, and neither are any of the computers on my local network.

DAVx⁵ is designed for the Android sync framework, which requires an Internet connection. Synchronizing without ever having Internet access is a special requirement, which is covered by the design goal of DAVx⁵ .

So people who don’t have access to the wider internet are “special requirements”? This is mildly infuriating. Why the hell do so many developers design their apps to simply NOT WORK if you have a device that never touches the internet? There are a shit ton of people in the world who have devices that cant connect to the internet!

In particular its annoying because you guys made the design decision to build an app for CalDAV, which does not require access to the internet, and you ADDED ON A REQUIREMENT FOR AN INTERNET CONNECTION!

And your app is the only option availible on f-droid too. Now i need to start shoping around for open source apps availible on the play store, which is a massive pain in the butt.

By the way, this does not only affect DAVx5, but all apps which use the sync framework, including the Android email app, Firefox (Firefox Sync uses the sync framework), messengers (contact lists are synced over the sync framework) and probably much more.

Of course firefox and email and messengers dont work when you dont have internet, those are all apps that at their core involve communication with other people in one form or another, which is what the internet is for.

But thats not what calendars are for. Calandars are just a way of keeping track of events, no communication with other people nessisary. Saying I cant sync my calander without an internet connection is like saying I cant sync tasks or notes to self or text files without a connection to the internet. Its entirly ignoring a big part of what people use calanders for.

@rfc2822 said in Option to change the IP address for the server:

What don’t you just create a WiFi with your notebook and use this WiFi from your phone? Or, the other way, create a WiFi on your phone (tethering) and then connect with the notebook to this WiFi?

That is what I actually do already! I connect the phone with the hotspot of the notebook because that is much faster than the Wifi network. But the hotspot IP did not work, only the IP of the notebook in the Wifi network. Your answer prompted me to check this again. Probably it was a missing firewall rule. Now it works! I use the hotspot of the notebook because that IP and therefore the server address remains the same (192.168.137.1), the IP of the phone changes with every new connection to the hotspot.

So thank you very much for addressing this!

(How) can I add the “solved” tag to this thread?

@allesaufhorst yes, I was affected myself on my production device about a year ago, however when I excluded it from battery saving of Samsung the problem started to disappear, and now I can’t reproduce it anymore…

I think adb logs would maybe help a little bit. Personally I think this is a bug in Android, but maybe we can workaround it by putting a hard-coded “wait” time before every sync is processed - however that would be very dirty…

@tartarian said in DavX thinks there is no internet even though there is:

That is fine but it would be nice if the app does not rely on the system’s false flags if it is conenected or not. Maybe some kind of override would be nice for sure.

DAVx⁵ is a sync adapter and relies on the synchronization framework of Android. If Android thinks there is not internet connection, it won’t call DAVx⁵ for synchronization.

Please make sure that Android APIs work as documented on your phone; otherwise apps which use those APIs can’t work well. DAVx⁵ relies on working Android APIs, like many other apps. For instance, you won’t be able to receive emails or sync your Firefox data “without Internet connection” as well.

I suggest to change the captive portal URL to something on your own server and de-block the connectivity check in your firewall.

BTW, it’s called DAVx⁵ or DAVx5. Please don’t call it DavX.

Hello,

2019-11-30 09:49:10 10217 [HttpClient] <-- HTTP FAILED: java.net.ConnectException: Failed to connect to /192.168.0.100:8443
2019-11-30 09:49:10 10217 [ui.setup.DavResourceFinder] PROPFIND/OPTIONS on user-given URL failed

There is no connection to 192.168.0.100:8443 from your Android device, so it’s probably a connectivity problem (firewall, …). Does it work when you access the URL from your Android browser?

In DAVx⁵ 2.6, there will be a warning when there’s no validated Internet connection. So when you see this, you will know there’s something wrong with the connection:

Thanks for the explanation. I guess it was a problem with Baïkal after all.

I have “fixed” it by switching to DAViCal.
Very intimidating documentation & UI, but almost nothing needed to be configured and it Just Worked.

So,

DAViCal is the server DAVx5 syncs everything on Android on the desktop I use vdirsyncer & khal for the calendar only (vdirsyncer still refuses to sync my contacts), and SoGo connector for contacts on thunderbird.

It’s been a long day.

@pescepalla Thank’s a lot! Your solution workes on my Xiaomi 5s plus with nextcloud on an own server in my LAN and using DAVx⁵ for synchronisation after I’ve searched two days where the problem comes from. By accident I installed nextcloud 15 and deleted and reconfigured DAVx⁵’s account. So I was not clear if it’s a nextcloud or a DAVx⁵ problem. Finally I found out in the nextcloud logs an entry

webdav Sabre\DAV\Exception\NotAuthenticated: No public access to this resource., No 'Authorization: Basic' header found. Either the client didn't send one, or the server is misconfigured, No 'Authorization: Bearer' header found. Either the client didn't send one, or the server is mis-configured, No 'Authorization: Basic' header found. Either the client didn't send one, or the server is misconfigured

Still misleading, I checked everything related with passwords and accounts.

Android doesn’t sync if it can’t connect to a working captive_portal_https_url, even if you choosed in the internet access settings for your network not to ask the question anymore and the internet works as far, as possible in China. And that with LineageOs. As many people not only using their own local nextcloud installation inside a LAN that is kind of a strange setting with Android in China at least.

Thanks again, @pescepalla !

Confirm the regression too.
got I9300 with replicant 6.0 0003

Long time ago, add account to davdroid installed from f-droid. Following upgrade from f-droid repository and work well with latest version of Davx5.

But have to reinstall os, reinstall Davx5, and cant register new account with the same stack of error when trying this url: https://domain.tld/baikal/html/dav.php
And when trying https://domain.tld/baikal/html/dav.php/calendars/user/work/, Davx5 print crash popup.

Install an old davdroid apk and work well. Work well with Thunderbird too for calendar and Inverse SOGo Connector for address book. Not a server side problem.

Thanks a lot for this software ! Happy to use it daily.

@devvv4ever Sorry for the delay in responding. I used the IP instead of the name, but I get the same result.

Here is the log
davx5-info.txt

Any thought will be greatly appreciated.

@mazeiva I don’t know. We’d have to know the actual reason why it’s not working to say why it’s working on other devices.

Maybe you can find something in your server (for instance, do the DAVx⁵/browser requests make it through to the server) and/or firewall logs?

Is it possible that you have multifactor turned on for Nextcloud?

If so, you can create a one-time password in your NC settings.

@moonlies Did you use an app password for the first account? In this case, the app password would stay valid even when the main password changes.

@rfc2822, may application was moved back to the old server.
now all cipherspecs are available again, nothing was changed on the old server !

Only my Nextcloud was first migrated to a newer server, there Nextcloud was updated from 13.0.7 to 14.0.4, the problems occurred.
now the Nextcloud has been moved back to the old server.

But now it is still Nextcloud 14.0.4 !
Could it be that it’s not the cipherspecs but the old DavDroid has a problem with Nextcloud 14.0.4?

Hello
I’m running owncloud 10.0.0.4 on a slow system and requesting a contact sync >450 entries (with pictures).
As far as i’m able to judge the client is requesting the whole addressbook and after timeout exception it want to retry a request of 10 entries. At this time the server is still running at 100% cpu duty collecting the previous request.
That leads to a bunch of apache instances on server-side which freezes the system for a couple of minutes and the client isn’t getting it’s requests within it’s (too short and unconfigurable) timeout.
For reference: setting the timeout to 180sec would very likely fix this problem