No sound from speakers on MacBook Pro except the startup chime

After plugging my headphones out, suddenly there is no sound from the internal speakers.
When I press volume buttons, I see a circle-backslash symbol below the speaker icon.

Restarting doesn't help. However I do hear the startup chime.
What should I do?


Solution 1:

Gently pluginng the headphones in and out of the jack solved the issue.

Solution 2:

The pins in the 3.5mm jack probably got stuck and gently reseating them should have resolved it for good.