I have a web page that shows the green padlock of the SSL certificate in the frontend, but when accessing the wordpress backend it does not appear. First, I do not know if it's silly.
At the same time some users have experienced that it gives security problem when they access from android phones, not iOS. They see the poster that can be an unsafe page.
I have other pages with Wordpress and the SSL certificate and they work perfectly. I do not know what it can be.
Issue resolved. It was the problem of the mixed content in backend. I regenerated the certificate and with the chrome element inspector in the backend I looked in "Console" and "Security" for the error. The error was a url of an image that pointed to "http" instead of "https". I deleted the image and put it back on the server and everything works correctly. I already have the green padlock on front and backend.
If in your original wordpress installation you configured the url with http instead of https, the internal links will remain http. You could try making that change in the panel, if applicable.
Specifically, to force the login and admin panel to be accessed with https, you can edit your wp-config.php and put
define( 'FORCE_SSL_LOGIN', true );
define( 'FORCE_SSL_ADMIN', true );
What kind of certificate are you using? Did you buy one, generate one free with let's encrypt, are you using universal Cloudflare SSL? Depending on how you have implemented it, the certificate chain that is configured in the vhost (from apache or nginx) may not be in the correct order. On the desktop and this is ignored, but Android is stricter.
Paste your domain into link and check if there are any warnings.