Hello
You need to grant permission sets, invoice posting authorizer, user per user group etc.
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Hope this helps
Yes, quite a few set up is required.
What I would do is, have a look at the user set up of the person who left the business and give the same permission sets, user groups, etc and company access to your new user (or yourself). if it is Aurena, you simply have to refresh the web page to inherit the new permissions. If it is IFS EE, you will have to clear security cache, log out of IFS and log back in to inherit new permissions granted. and you should be able to at lease see the screens, and data.
NOTE: Screen access is granted by permission sets. Data access is controlled by Company access, invoice posting authorizer, user per user group set as mentioned above.