Hello info2044,
Welcome to Community! QuickBooks Online provides options for managing your chart of accounts, so your books remain organized. I can understand the impact on your day, when you're unable to enter your bills effortlessly. I would be glad to assist!
Follow these steps to restore your GST/HST liability account;
1. Open your Settings ⚙, then select Chart of accounts
2. Next to the printer icon, tap the Settings ⚙
3. Select the Include inactive checkbox
4. Locate the account you want to use again, then select Make active.
You should be able to proceed with entering your bills, without error.
Should you require additional assistance, please don't hesitate to contact us outside of this forum. We would enjoy the opportunity to work with you personally, and ensure you're able to accomplish your QuickBooks goals without delay!
Feel free to reach back out with any other questions. We would be happy to help!