According to Gofundme FAQs there are several reasons for your funds being on hold:
If your email address has not been verified before 14 days of your first donation, donations to your fundraiser will be paused. To accept donations again, search for the email titled “Verify Your GoFundMe Email” and confirm your email address.
Update fundraiser information.
The fundraiser is under review.
Please, contact Gofundme customer service via live chat for further information.