Bug - Failed to login: Invalid session

Dear Sir or Madam,
 
I am writing to you regarding the Minecraft launcher problem. I was hoping you could help me with it.
 
It started when I came back today from my vacation after 6 days of inactivity today. Whenever I start the launcher and join any online servers it keeps throwing this tab. 
 
[_11:53_]

 I restarted and redownloaded Minecraft many times now( Even PC), yet nothing happened
 
Your services failed to help me fix it when I check similar issues posted by other players.
I hope my this letter will reach out to you.
I am looking forward to hearing from you, as soon as possible,
Kind reagrds,
Kahai