Verify your YouTube Account
In order to upload videos longer than 15 minutes you will need to do a one time account verification. Click here for instructions 
to verify your account by phone.
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Summary
Option 1:
Go to https://www.youtube.com/verify and follow the instructions.
Option 2:
By default, you can upload videos that are up to 15 minutes long. To upload longer videos, verify your account with the following steps.
- On a computer, visit the upload page at www.youtube.com/my_videos_upload
- Click Increase your limit at the bottom of the page, or visit https://www.youtube.com/verify
- Follow the steps to verify your account with a phone. You can choose between receiving the verification code through a text message (on a mobile phone) or an automated voice call.
From: https://support.google.com/youtube/answer/71673
Click here for instructions to verify your account by phone.