ShortPoint Add-In for SharePoint Online and Office 365 will not work without turning on scripting capabilities.

It takes about 24 hours for this change to take effect

Step 1: 

Login to your Office 365 admin center page with administrator account, then choose Admin


Step 2: 

Go to SharePoint Admin Center


Or in the new admin center

Step 3: 

Open Settings

Step 4: 

Allow users to run custom script on personal sites and self-service created sites

Step 5: 

Click Ok

It takes about 24 hours for the change to take effect

Detailed Steps from Microsoft: Turn scripting capabilities on or off

NEXT: Setup App Catalog