Unknown error on export

suddentely, i cant export my photos. LR gives me un unkow wrror, so, i dont even know what the problem is. i re-installed, I gave the PC to an IT colleague, that reset some settings, and it worked 3 times. after it, it stopped exporting again.

i changed several exportings settings, but the problem dont go away....

PS: how the f**** can i talk with somebody of Adobe?! we are paying for a software but also for a service, and i cant find any direct contact to them. only stupid bots and FAQs!

thank you for your support