Is this when installing or activating, two different things? 

Is this for ANY base plugin or just for a third party plugin? 

It's when activating on the available plugins page.
Even the base plugins will not activate.

OK shared hosting or dedicated server?

are you absolutely sure that php_openssl is installed and enabled?

It's my own webserver with shared hosting.
Checked the php info and openssl is enabled.

Interesting, everything i found so far points to openssl.  This may have to be handled by ross or aliya as im at a loss right now.  Lets try to give them some info they may need so they dont have to ask. 

Can you share a screen shot of the openssl portion of your PHPINFO display.  

Does your server meet all the specs on the RIGHT SIDE of this page?   http://www.oxwall.org/hosting

Do you have any other issues with the site that may relate to this?

Have you disabled all third party plugins and the issue is still there?

Do you have dev and debug mode on at the same time?

What is your PHP version according to PHPINFO() ?

As a last resort:  Have you tried to do a clean install in another directory to see if the issue is there as well?  We want to try to isolate if the issue is on the server side or the software side.   If you do a new install somewhere else on the server and it works then the issue is on the software side (plugin conflict or other issue).  If it does not work then it is server side config somewhere. 

This should give ross or aliya enough info to further assist you in the issue.  

Thanks for your effort Dave!

My php version is 5.5.9 with fcgi enabled.
The oxwall installation is quite new. Installed it today and haven't installed other plugins.

Your welcome :),  i do have a free plugin to test the system, but if your not able to activate anything it wont help right now. 

https://developers.oxwall.com/store/item/1356

Maybe after you get this issue fixed you can try it to check it out.  You will get a better report if you have shell_exec enabled. 

I will keep thinking on this, but ross or aliya will be in tonight at about 11pm or so mytime (im in the USA) about 13 hours from now, lets see what they say on this. 

Here is where that error comes from, its the only place i found it in the whole script so it has to come from here. 

its in ow_system_plugins/admin/controllers/plugins.php  line 653

the code is 

    // get remote info about the plugin

        $itemData = $this->storageService->getItemInfoForUpdate($params[BOL_StorageService::URI_VAR_KEY],              $params[BOL_StorageService::URI_VAR_DEV_KEY]);

       if ( empty($itemData) )        

       {  

          $feedback->error($language->text("admin", "manage_plugins_server_invalid_responce_error_message"));

          $this->redirect($router->urlForRoute("admin_plugins_available"));        

       }

So it appears its not getting the plugin key or the developer key for some reason.

check the ow_base_plugin table and be sure you dont see any obvious issues with that table.  It might not hurt to run the db repair feature in your cpanel on that database. 

so your serving up your php via fast cgi. Did you set up the fast cgi or did someone else?

Im starting to think its something with the DB here, do you happen to have the mysql (i) extension enabled on your server? 

No errors in your error log, clear your log and then try and see what error shows. 

Thanks Dave :)

Thats right but this seems to call the function "getItemInfoForUpdate" from storage.php line 67. The error should be somewhere there, or am I wrong?
When there is a error when getting the plugin keys from the plugin-server, then the message "manage_plugins_server_invalid_responce_error_message" makes sense.
It seems my server can not get a connection to yours. But why??? Do you establish a ssl connection with the server?

Sadly no entry in any logfile so far. Checked the apache logs too.

Yes, installed everything on the server from the ground up. fcgi too. :)
I use Froxlor as admin panel. It's not as popular as cPanel or Plesk but quite good and has a clean ui. Like it. :)

The database table looks really normal, I think:

Btw: I'm able to upload your plugin with the admin backend.
But as expected I can't enable it too.

you can enable it manually via the plugins table just change isActive field to 1 instead of 0

I dont see anything wrong with the table either.  I will check that function.  Also yes i do a connection with my plugins. I check for mysqli then mysql connections.

Actually that function is on line 199 of the storage_service.php file  which grabs data from another function on the plugin info update event.. 

which i believe we will find that your not getting a good connection with the DB, because the data var is empty and passes it back to the other file as empty, but im not 100% sure about the DB issue but it seems logical right now.  

In the table are only the plugins which has been activated yet. :/

If you find out what's wrong, let me know please. I'm out of luck so far.
But when it's an db issue some other features won't work too. But everything else seems to work.

If you want to test with my installation I could give you a ftp account and the admin account of oxwall. Maybe it helps you to find the bug.

OK ill keep noodling over this..   I dont get into other peoples systems but ross or aliya might have to.  Hopefully they can reply soon. 

I've installed everything again and the error still exists.
Interestingly I get the following error, when I check for oxwall updates:
"Unable to connect to the remoteserver"

It seems the oxwall installation can not connect to your servers. How do you connect? With curl?

Hey Dave! I've got it to work! :))
Curl was deactivated in the php.ini of the oxwall installation.
Sorry for the inconvenience. But maybe it helps others with the same problem in the future. :)

Thanks for sharing, glad you got it sorted :)