If you are unable to access DocHub and receive a page about how "DocHub.com is blocked. The person who setup this computer has chosen to block this site.", it's most likely due to Google's SafeSites filter and DocHub being incorrectly flagged.
To fix it without turning off the SafeSites filter, an administrator can whitelist (allow) DocHub.com by following the steps in the articles below:
If whitelisting DocHub.com for your entire domain doesn't unblock it, then you might have another filter blocking it on another level such as a sub OU (Organizational Unit) within your Google Workspace (GSuite) account.