This basically tells that MySQL handles the maximum number of connections simultaneously and by default it handles 100 connections simultaneously.

These following reasons cause MySQL to run out connections.

1. Slow Queries

2. Data Storage Techniques

3. Bad MySQL configuration

I was able to overcome this issues by doing the followings.

Open MySQL command line tool and type,

show variables like "max_connections";

This will return you something like this.

+-----------------+-------+
| Variable_name   | Value |
+-----------------+-------+
| max_connections | 100   |
+-----------------+-------+

You can change the setting to e.g. 200 by issuing the following command without having to restart the MySQL server.

set global max_connections = 200;

Now when you restart MySQL the next time it will use this setting instead of the default.

Keep in mind that increase of the number of connections will increase the amount of RAM required for MySQL to run.