Try restarting minecraft, if that doesn't work reset your internet by unpluging your router for 10 seconds then reconecting it.
Also try logging out of your minecraft launcher, then logging back in. That should fix it (in most cases).
Usually happens when you login a new instance of minecraft with your old one open. Just close & reopen your launcher, will most likely force you to relogin and give you a new sessionid.
@SkylixMC dont you fucking dare tell me that this isn't an inapropriet use of ratings, this is rediculous.
No, this has gone on long enough and it needs to stop. Ive reported this shit before and all you get is the same response "well you cant really define inapropriet use" They have this rule yet there is NO enforcement whatsoever. A line NEEDS to be drawn and @Udemy you need to understand what kind of shit ive been putting up with for months before you i even consider your opinion on how i should conduct myself. You want to see examples go back to threads from today to 6 months ago. Your mind will QUICKLY be changed.