Thank you for posting here in the Community, @elmassian.
I'd be glad to help fix the error you're getting while working with QuickBooks Desktop (QBDT).
If you're attempting to connect to bank or downloaded transactions and receive the Error code OL-301 or 393, this may happen if:
An online account is not set up properly in QuickBooks Desktop or at the bank.
The bank is waiting for identity confirmation.
The bank server is not responding due to server maintenance.
The Quickbooks Desktop company file may be damaged.
To resolve the error:
First, you need to create a new test file:
Go to the File menu.
Click on New Company.
Click the Express Start button.
In the QuickBooks Setup window, enter all required information then click Create Company.
If you receive the same error message, this typically indicates that there is a problem with your bank. Please contact your bank to verify your account information, check for server outages and report the problem.
If you do not receive an error message, this means that the problem is not with your bank, you may need to deactivate and reactivate or reset your account connection. If the problem persists, you need to check for inactive accounts in QuickBooks. If the problem continues, I suggest verifying the data integrity.