The underlying provider failed on Open - asp.net

Question

I made 3 Ajax processes to run the below code at the same time.
but one of the processes throw exception that message says "The underlying provider failed on Open."
try{
orderRepository orderRepo = new orderRepository(); // get context (Mysql)
var result = (from x in orderRepo.orders
where x.orderid == orderno
select new {x.tracking, x.status, x.charged }).SingleOrDefault();
charged = result.charged;
}catch(Exception e){
log.Error(e.Message); // The underlying provider failed on Open.
}
And, I run the 1 Ajax call that failed before, then It passes through.
It happen to 1 of 3 (Ajax) process, sometimes, 2 of 5 process.
I guess it because all process try to using Database same time. but I couldn't find the solution.
This is my connection string,
<add name="EFMysqlContext" connectionString="server=10.0.0.10;User Id=root;pwd=xxxx;Persist Security Info=True;database=shop_db" providerName="Mysql.Data.MySqlClient" />
Anybody know the solution or something I can try, please advise me.
Thanks

Answer 1

It sounds like a problem because of concurrent connection with SQL Server using same username. Have you tried destroying/disposing the repository(or connection) object after using it?
Give it a try:
try{
using( orderRepository orderRepo = new orderRepository()) // get context (Mysql)
{
var result = (from x in orderRepo.orders
where x.orderid == orderno
select new {x.tracking, x.status, x.charged }).SingleOrDefault();
charged = result.charged;
} // orderRepo object automatically gets disposed here
catch(Exception e){
log.Error(e.Message); // The underlying provider failed on Open.
} }

Answer 2

Not sure if it matters, but your provider name is Mysql.Data.MySqlClient and not MySql.Data.MySqlClient (if it is case-sensitive, this could be the cause).