Server unknown Error

I can not use my hard disk in the WD N900N one TB I have. The error is: server unknown error

500 Internal Server Error
I have installed a new firmware and an older firmware nothing helped. I can not find an other community from WD where I can ask my question. I don’t want to format my hard disk because of the photos i have on it.
Who can help me?

You may want to have a look at this KBA:
https://support.wdc.com/knowledgebase/answer.aspx?ID=9425&lang=en

Thank you for your help. I have an internal hard drive. Maybe this will work also for my internal drive, but o don’t want to format it. Maybe i can configure it without formatting, but I don’t know if that is possible.

What I don’t understand is that i can acces the hard disk with my toshiba laptop (with \http adres on internet explorer) and i can see all the files on it and copy files to it. But i can not turn on the mobiel or web access. An when I try to turn mobiel access it asks to turn it on and when i click yes i get the error.
And no i also can acces it with my macbook. So i have acces when i am connected to the router but no acces externally.

I still can not acces my internal hard disk. I have formatted the hard disk, I also have reset the router to factory settings still internal server error 500.
And i have tried internal hd recovery bu after 10% it says too slow internet speed (i have 150MBit speed) or network is down.