Trouble logging in to Admin, using iOS-App and Sharing

Hey there!

I am owner of a german comic book-blog called DeinAntiHeld.de – https://www.deinantiheld.de. I’m blogging for three months now, very basic stuff, hosted on a server at german Provider Strato. A few days (I think) after updating to 4.3.1, after working fluidly and nice for three months the s**t hit the fan.

When I try to log in at blog.deinantiheld.de/wp-admin, it takes me round ten times until i am able to log in. Most of the time the browser keeps loading around 30 seconds, then responds with the error message “Safari can’t open the page, the server unexpectedly interrupted the connection” – roughly translated. Same with Chrome or Firefox.

Once connected everything is working just nice and fine. Obviously something is going wrong logging in to the dashboard. Unfortunately, the iOS-App, that is very important for my workflow seems to authenticate with every refresh, what makes it practically useless right now.

What I tried together with my admin (who has much deeper technical knowledge than I do)

– Turning off all Plugins and Themes to see if one of them is causing trouble – Negative
– Manually installing WP 4.3.1 again – Negative
– Manually Downgrading to WP 4.3.0 – Negative
– Replacing the WP-Admin – Folder – Negative
– Updating PHP to 5.6, back to 5.5, back to 5.3 – All Negative
– Trying to manually set the Memory Limit with .htaccess, wp-config or php.ini – Negative
– Reverting a complete FTP Backup of my Provider from before the trouble started – Negative

So after many long calls with Strato until the early morning and my admin checking and repeating all my steps I was already accepting my fate, switching to using the browser Admin on my iPad instead of the iOS App and accepting that I had to try around ten times to log in before I finally do. Strato keeps denying it is a server problem. And to be honest, neither me nor my admin are sure it is, right now.

The other big problem resulting from this really, really frustrating situation is that all my planned posts are not automatically shared on Facebook and Twitter anymore. I tried logging out and in to these accounts in my settings, but keep getting the Jetpack-Error-Message 10520. 30 attempts in a row, hoping to find a “weak moment” like I always to trying hard enough to log in to the admin-board.

I deleted an reinstalled Jetpack, but the problem is still there.

I am really desperate for help right now. My blog is increasing popularity. But although I have workarounds for all these issues, they all disrupt my time-management. my daytime job is of course not being a Comic-Blogger. I use very few and simple plugins and a popular theme called bloggr, with no modifications except for custom css with Jetpack. All Plugins, themes and language packs are up to date.

EDIT – The page itself is running nice and smooth, all issues are only concerning the admin level!

Please, someone help ??