i just paid and I can't open the new world in realm+

I don't know why 

I pay for the realm and want play with frds 

but I can't open the new world , when it's start to download and it come out a (error) message to me 

I am very frustrated with the situation 

I have spent  a lot of hours to try to find out and fix this problem however it not work!!!

 

thank you