Dashboard Sub-domain SSL MultiSite

Hello,
I have problem with user signup and login ssl in my site ,
when user login from main site see his Dashboard with link to his domain
Dashboard and site , Visit site link is show http://subdomain.mysite.com but the Dashboard show : ssl , https://subdomain.mysite.com .
When user click on Dashboard got SSL error

signup Erorr image

login Erorr image

how can fix that

Thanks