Low output voltage

Hi guys i have progressed with my project and its time to ADD SOME LED’s, after wiring some up i noticed they were not working so i just uploaded the basic blink project and the LED’s were not lighten up.

But then i noticed that they were lit but very very dim, i then used a voltmeter over the pins and the out put is about 1.8V or lower.

Any idea why this would be?

May I know what microcontroller board you are using and in which pin of it you have connected the LED.