If the server has an "0"(zero) in it then it will continue to crash. The problem is item render being bound to the "0"(zero) key.
Read this thread:
You can either copy and paste the ip, or rebind the key.
There is a simple way to rebind the key.
Complete the steps as follows:
1: Launch FTB launcher.
2: Select Mincrack modpack.
3: Launch the modpack.
4: Go into "Options" when presented with the Minecraft main menu.
5: Click on "Controls...".
5: Scroll all the way down to "ItemRender".
6: Click on "ItemRender".
7: Bind it to a key you will never press on any occasion.
8: Save and exit to the main menu.