Payment Extensions not showing

[Saxon]

Hi all hope someone can help i have two problems but related to the same thing payment.

I have setup a paypal business account and have my API information but my problems are ass follows

1: when i set paypal or paypal pro they do not show in the checkout although they are both active i have tried a few and the only one that will show at checkout is bank transfer ?

2: when i setup paypal pro i put my details in a try and test it i get the following.

PayPal Error: Security header is not valid

Thanks again for any help i seem to keep asking for things 

[Saxon]

I have gone over to stripe after reading some reviews and looking at charges was the best option in the end plus it is all working with simple setup tested and working.

[Basara]

Hello.
Paypal security header is not valid error message can be shown because you have set up live credentials and you have turned Test mode to ON.