RSS Error: WP HTTP Error: Missing header/body separator

Hello. Since updating to WordPress 4.6 I am getting this error message. I can no longer add plugins and none of the existing ones work —RSS Error: WP HTTP Error: Missing header/body separator—

I have read on other threads that this could be due to the cUrl.exe function being disabled but in my case the funtion is activated.

I get the message when I try to use any of the plugins. On the general plugin page the message is: “Ha sucedido un error inesperado. Puede que haya un problema con www.remarpro.com o con la configuración de este servidor. Si continuas teniendo problemas, por favor prueba en los foros de soporte.”

In English this means: “an unexpected error has occurred. There could be a problem with www.remarpro.com or with the configuration of this server. If you continue to have problems, please try the support forums”.

So here I am.

Please help.