Unable to login to admin dashboard

[AdmiralM]

I've installed a new PS 1.6.1.8 on debian server(php 5.6.26, apache 2.4.10), changed the default language and the installer was like it was missing some styles. After the install I was unable to login to admin, using correct login info after entering the info into the form the page just froze(my guess it was a 500 error).

I've erased all the mysql and files and started over the issue didn't appeared anymore.
After a couple of days of tweaking the admin settings and setting the products variables, attributes, etc. Today I've changed the admin folder name, trying to login back to admin dashboard didn't work anymore. I've encountered the same issue as in the first time I've installed PS.

 

The PS install doesn't have any files manually modified. Checking the logs I've encountered the following error:
 

XXX.xxx.xxx.xxx - - [07/Nov/2016:17:12:41 +0200] "POST /adminXXXXXX/ajax-tab.php?rand=1478531560010 HTTP/1.1" 500 8878 "http://Mystore.com/adminXXXXXX/index.php?controller=AdminLogin&token=de887920121dda65d807fdd1fa08109b" "Mozilla/5.0 (Windows NT 6.3; WOW64; rv:49.0) Gecko/20100101 Firefox/49.0"

Any ideas on how to solve this?

[sun6]

i have the same problem...

[AdmiralM]

So far I've found the following trick that solved and also pointed out the issue:

I use 2 languages on PS 1 is English which is used as default language for admin and another language for front end.

It seems that my second language is causing the issue, when I have it selected as default language the login form is missing the translations(the blue login button is just a blue box, no label text over it).

So to solve this issue I've changed from database into the ps_configuration the row containing PS_LANG_DEFAULT from one lang id to another(you can check the id number in ps_lang).

 

For the moment I will try to translate all the strings and then switch back the default language to test.

[sun6]

thank you !

Edited November 7, 2016 by sun6 (see edit history)

[Rhobur]

or this, https://www.prestashop.com/forums/topic/564352-important-for-those-who-can-not-access-to-bo-after-upgrade-from-1617-to-1618/?do=findComment&comment=2433007