If you have been utilizing the Basic (Legacy) option for your NetSuite integration, that option will no longer be supported. You will need to update to the Token Based Authentication option.
To Update, you will navigate to Settings > Reports (under Personal Reports section) > NetSuite > Edit (by clicking the pencil icon) and switch to Token option and then enter required information as outlined below.
Token
1. Enter your Netsuite Token ID, Token Secret, and Account ID. Must be the Token information for a Netsuite Administrator account.
Follow directions below to retrieve Token ID and Token Secret:
2. Login to Netsuite Admin account > Setup > Company > Enable Features > SuiteCloud > Manage Authentication > Check "Token-Based Authentication" > Save.
2a. Setup > Company > Enable Features > SuiteScript > Check “Client Suitescript” and “Server Suitescript” > Save.
2b. Customization > SuiteBundler > Search & Install Bundles > Search for “TriNet Expense” > Click on “TriNet Expense - TBA” > Click blue “Install” button. 
2c. Lists > Employees > Employees > Edit "yourself" Employee > Access > Select Role "TriNet Expense Integration" > Save.
2d. Search for “Tokens” in the search bar at top of screen > Click on “New Access Token” >
Application Name “Expense Application Token Based” > User “select self” > Role “TriNet Expense Integration” > Save
3. Token ID & Secret displays one time only. Copy/paste information in Expense Management
4. Click Save
If you have any issues with the update to NetSuite Token option reach out to our team at: CloudProductSupportTeam@trinet.com