Replaced light switches not working

[Scm00038]

I'm in the process of renovating my hallway and the downstairs has a single light controlled by 4 switches. I've been replacing each switch and testing after each one, however one of them I have changed and now it does not work to turn the light on or off. Other switches still work. All wires fitted into the new switch exactly the same as the old one. Totally stumped - any ideas?

 

[UNG]

Do you have any pictures that may give us clue

 

[littlespark]

So 4 switches for one light? So two of them would have to be intermediate switches? You didn’t buy double pole switches by mistake?
Both have 4 terminals for wires in the back

 

[Scm00038]

So 4 switches for one light? So two of them would have to be intermediate switches? You didn’t buy double pole switches by mistake?
Both have 4 terminals for wires in the back

Only 1 is an intermediate. Two are two way and two are one way.

 

[Scm00038]

Do you have any pictures that may give us clue

Picture attached of the one causing me issues

 

[Scm00038]

Do you have any pictures that may give us clue

Left side with yellow and blue is for hallway light. Right side is for outside light.

 

[westward10]

I agree with @littlespark if four switches control one light I would expect two intermediates. Can you show the other switches.

 

[westward10]

Does the outside light work and stay working when you switch the other switches.

 

[Scm00038]

Does the outside light work and stay working when you switch the other switches.

Yes - I've found the cause now. Not enough intermediate switches

 

[littlespark]

As long as it’s all sorted