Multi Shop Error 403

[Photo Booth Animatio]

Hi everyone, hoping someone can help me please. I've tried to make a second shop in Prestashop with it's own domain name seperate from the original shop, but when trying to open the second shop I keep getting error 403, very frustrating as I'm losing possible clients until I can get this rectified.

I paid for a developer/programmer to take a look at what I had done and he found i had done the set up correctly. he did suggest that I needed to attach the new domain name to the end of the original shop to open the new one, which really defeats the whole idea of seperate shops.

Can someone tell me I wasted money on using this guy and I was fleeced or was correct in saying what he told me.

I'm now also finding an intermittent problem getting access to the back office.

I like using Prestashop as it fits my purposes but as a none developer it is a very frustrating programme to get your head around not having any computer training at my age in life.

Could someone please get me back on track to open up the new shop as I'm really considering looking elsewhere for a less stressful programme.

Thanks for reading.

Paul.