Sorry for the confusion. DriveHQ's FTP/FTPS/SFTP Hosting features are business features and require a business subscription. Please understand that very few personal users need FTP/SFTP. For personal users, DriveHQ's client programs like DriveHQ FileManager, WebDAV Drive Mapping and DriveHQ Online Backup are much better and easier than FTP/SFTP.
In general, DriveHQ's free and personal service plans cannot be used for business, except for trying our business features. We also offer 2-week free business trial, which you can sign up online. You can find the information online in the FTP Features page and the Pricing & Plans page ("compare service plans" page), please see the screenshot below:

If the free/personal FTP feature worked fine before, it was because we did not strictly enforce some limitations.
If you need FTP for long term, please consider ordering a business subscription. The lowest business plan is the "Business Basic Plan with 3 users". The business basic plans are low-cost plans optimized for small businesses with small amount of data.
If you believe you use it for "personal purposes", please contact us. We can offer you a special discount.
If you use it for IP camera / NVR cloud storage, please use our CameraFTP.com service instead. CameraFTP offers the most flexible and versatile cloud recording (home/business surveillance) service.
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We have a very detailed step-by-step FTP tutorial video. It covers many topics such as:
- Regular FTP/SFTP features (Using FileZilla FTP client software);
- Group user creation and management; (incl. creating guest accounts for external clients)
- Storage allocation;
- Folder sharing and access control,
- Set the default FTP folder.
...
Please watch the tutorial video at: https://youtu.be/iGdBX4F1e-w