Today my Lightning sandbox is having some serious behavious issues. 
I run into following errors:

• Unfortunately, there was a problem. Please try again. If the problem continues, get in touch with your administrator with the error ID shown here and any other related details. An internal server error has occurred Error ID: 1986783592-9485 (1990134024)
• Uncaught TypeError: Cannot read property 'b' of null throws at https://cs88.lightning.force.com/auraFW/javascript/ywi4clSWfDw6pOdt8rkxkQ/aura_prod.js:268:162

When I refresh the window, the error disappears and I can continue working untill the next one appears, and so on.

Anyone have any clue what is happening?