Error when using phpMyAdmin's Designer to create ERD

Hi, 

When I tried to use phpMyAdmin's Designer to create ERD in non-production environment of Appian Cloud, I got "Error in processing request Error code: 500 error text: error (rejected) It seems that the connection to server has been lost...."

I suspect it is because we only have one database called Appian with nearly 900 tables.

I wonder anyone has solution(s) to this problem.

PS. I couldn't see Create database section under Databases tab. (I was hoping to resolve this problem by creating a new database to import the selected tables from Appian)

Thanks in advance.

Cheers,

Ben.