When we activate WPML String translation plugin with Views activated on a site we get a white screen. In Apache error log, we see the following php fatal error:
PHP Fatal error: Using $this when not in object context in /... /wp-content/plugins/wp-views/embedded/inc/WPML/wpv_wpml.php on line 1591, referer: https:// ... /wp-admin/admin.php?page=toolset-settings
We can activate WPML string translation without a problem if we first deactivate views.
I suspect that this issue is being caused by your php version. What I would recommend that you do is to update your php version to at least 5.6 as currently you are running version 5.5 which is below the minimum requirements of wordpress itself.
However, on another test site, on the same server, I have activated both the WPML plugin and the Toolset plugin which caused the white screen - i.e. running the same php version - and there is no problem on that site.
It seems the PHP version is not the problem in this case?
I have cloned the site with the issues within the same network, disabled all plugins on that clone and switched to default theme. Then activated WPML plugins inc. string translation. No problem. Then I activated toolset views: white screen appeared. So I guess the problem is with the wordpress network config and not with the server config...
What would be good approach to troubleshoot this further?