No administrator logins found, even thought the file is there

I have never seen this behavior before.
OpenCart admin login screen will not authorize any valid administrator email address / password combination. We have 3 none of them work. Created a 4th manually, ditto.
The website is up and functioning, so I know access to the SQL database is working. However, admin logins fail with a No Match for UserName / Password error message. Forgot password fails with no such email address.
We are effectively logged out of site administration.
It is not a browser issue, as I have tried on two different browsers AND mobile. All have the same results. There is nothing in the error logs. To the best of my knowledge, no changes have occured to the website reently. Site host says it's not them. Everything was working correctly 3 days ago.

I'm stumped. Any pointers on what might be causing this behavior?
Any assistance cheerfully accepted.
OC 4.0.2.2

UPDATE: Found this in the php logs:

[30-Sep-2024 16:14:18 UTC] PHP Fatal error: Uncaught Error: Failed opening required 'C:/wwwroot/HarborSales/system/startup.php' (include_path='.:/usr/local/php81/pear') in /home/customer/www/harbor-sales.com/public_html/vivid/index.php:24
Stack trace:
#0 {main}
thrown in /home/customer/www/harbor-sales.com/public_html/vivid/index.php on line 24

Someone must have done any changes, otherwise it's not possible what you are describing ..

You many "admins" do you have?
And how many of them have access to the files?
And have the hoster eventually changed some on the server?

And, have you already checked if the mentioned file is there?
And if not, added it again?

DaveRiba wrote: ↑

Sun Dec 01, 2024 4:42 am

UPDATE: Found this in the php logs:

[30-Sep-2024 16:14:18 UTC] PHP Fatal error: Uncaught Error: Failed opening required 'C:/wwwroot/HarborSales/system/startup.php' (include_path='.:/usr/local/php81/pear') in /home/customer/www/harbor-sales.com/public_html/vivid/index.php:24
Stack trace:
#0 {main}
thrown in /home/customer/www/harbor-sales.com/public_html/vivid/index.php on line 24

What are your permissions for the site folders/files?