This could be for a number of reasons the first thing to do is check that the user account for the API is not locked out. To do this:
Check what username and password are being used for the API attempting to connect to Access Financials.
Go to https://go.accessacloud.com and login with those credentials
If a Captcha prompt (I'm not a Robot) prompt appears, select the appropriate images.
Test the API connection in the 3rd party program
If this does not work or you are unable to log in, check the user name exists:
Ask an Evo Administrator to log in
Click Members
Search for the username
If the user does not exist, you will need create it and invite the user.
The last thing to check is that the user has access to Access Financials within Workspace.
Ask an Evo Administrator to log in
Click Members
Search for the username
Click the 3 dots menu and select Manage roles.
Find the Financials Database and give relevant access.