I'm facing a problem with one of my Sandboxes. Today I noticed that Access Token received from Connected App doesn't work (Session expired or invalid - INVALID_SESSION_ID). It's weird because everything was working fine on Friday. I created another app, but it still has the same problem. I also created Connected App on my private Developer Org and I still can't retrieve any data. I'm suspecting, that it can be general Salesforce problem, do you have the same problem with your connected apps?
Thanks in advance.