I can not activate a nether portal

Put the summary of the bug you're having here

I expected the nether portal to activate

What I expected to happen was...:
the nether portal would activate with flint and steel

What actually happened was...:
nothing

Steps to Reproduce:
1. Put a step by step guide on how to trigger the bug here
2. craft the nether portal frame
3. craft a flint and steel tool
4. attempt to activate the portal, it wont work. PLEASE HELP