invalid session

So i have tried almost everything i could see online, to solve a consistent "invalid session" on all minecraft servers i've tried logging into. 

so far i've tried:

• relauching minecraft
• relogging into my account
• restarting my pc
• opening two lauchers at the same time
• resetting my ip address
• resetting my tcp / ip stack
• attempted different versions (with and without optifine)
• attempted different servers

nothing has worked so far, and i have no idea what else to try at this point