Diagnosing and fixing SyteLine session timeout errors
SyteLine session has timed out please log in again error
Also searched as
- SyteLine keeps logging me out
- CSI session timeout every few minutes
- SyteLine IDO session expired error
- SyteLine web client session timeout too short
Short answer
SyteLine session timeouts come from one of three independent layers: the IDO Data Service session timeout on the app server, the IIS/application pool idle timeout for the web (Mongoose Web) client, or a load balancer/proxy idle timeout in front of a CloudSuite hosted environment. Fixing the wrong layer is the most common mistake - you need to identify which layer is actually expiring the session before changing anything.
Applies to: SyteLine 9.x, CloudSuite Industrial (CSI) 10.x, both .NET smart client and web (Mongoose) client
Find and adjust the right timeout layer
- 1Note whether the timeout happens on the .NET smart client, the web client, or both - the smart client uses the IDO Data Service session, the web client also depends on the IIS session and any front-end load balancer.
- 2For the .NET client and IDO service, check the session timeout setting on the IDO Data Service (in IIS, under the IDO Data Service application, or in the SyteLine Server Configuration if using a service-based deployment).
- 3For the web client, check the ASP.NET session timeout in the web.config for the Mongoose Web (or CSI Web UI) application, and the associated application pool's idle timeout in IIS.
- 4If the environment is CloudSuite hosted (multi-tenant or single-tenant AWS), the timeout may sit at Infor's load balancer/ingress layer - open a support ticket with Infor if on-prem settings are already correct and the session still drops early, since customers cannot change that layer directly.
- 5Check for any reverse proxy, VPN, or corporate firewall with its own idle-connection timeout (common at 15-30 minutes) sitting between users and the SyteLine servers - this is a frequent, overlooked cause for users on VPN.
- 6Confirm client-side keep-alive or polling settings are not disabled - some SyteLine web client configurations rely on periodic background calls to keep the IDO session alive, and browser extensions or aggressive tab-suspension can block them.
- 7After adjusting a timeout value, restart the relevant IIS application pool (not just recycle) to ensure the new value is picked up, and test with a session left idle for slightly longer than the old timeout to confirm the fix.
The layered nature of SyteLine session timeouts
SyteLine's architecture means a 'session' is not one thing. The .NET smart client authenticates and holds an IDO session against the IDO Data Service (an IIS-hosted service). The web client additionally has its own ASP.NET session and, in CloudSuite deployments, sits behind Infor-managed load balancers with their own idle timeouts. A user reporting 'I keep getting logged out' could be hitting any one of these, and the fix is different for each.
The practical diagnostic is timing: if the session drops at a very consistent interval (e.g. exactly 20 minutes of inactivity every time), that is a strong signal of a specific configured timeout rather than a network blip. If it is inconsistent, look at network infrastructure (VPN, proxy, wifi drops) instead of application settings.
On-prem: where the settings actually live
For on-premise SyteLine, the IDO Data Service timeout is typically configured through IIS Manager on the application server, in the IDO service's web.config (sessionState timeout value) or via SyteLine's server configuration utility depending on version. The web client (Mongoose Web / CSI Web UI) has its own separate web.config sessionState entry and its own application pool idle-timeout setting in IIS - these two values are independent and should generally be set consistently to avoid a client session outliving its IDO session (which produces confusing 'session expired' errors mid-task).
<!-- Typical ASP.NET web.config sessionState entry -->
<sessionState mode="InProc" timeout="30" />
REM IIS application pool idle timeout is set separately in IIS Manager
REM Application Pools > select pool > Advanced Settings > Idle Time-out (minutes)
CloudSuite / hosted considerations
In CloudSuite Industrial multi-tenant or AWS single-tenant deployments, customers do not have direct access to the load balancer or ingress timeout settings - these are managed by Infor. If on-prem-style settings (where accessible) are already correctly configured and sessions still drop earlier than expected, the next step is an Infor support ticket referencing the exact idle time observed, since it may require a change on Infor's side rather than the customer's.
Common pitfalls
- !Changing only the IIS application pool idle timeout without also updating the ASP.NET sessionState timeout - the shorter of the two still wins.
- !Assuming a CloudSuite hosted timeout can be changed the same way as on-prem - it usually requires an Infor support request instead.
- !Overlooking corporate VPN or firewall idle-connection timeouts, which can cut a session well before any SyteLine-configured value is reached.
- !Setting timeouts extremely long as a workaround, which increases the number of concurrently held IDO sessions and can affect license/session counts and server memory.
- !Not restarting (recycling alone is often insufficient) the IIS application pool after a web.config change, leading to inconsistent behavior across users hitting different worker processes.
How an ERP-grounded AI assistant handles this
ERPray grounded on a customer's SyteLine environment can pull the actual configured timeout values from IIS/web.config documentation the team has stored, cross-reference them against a user's reported drop time, and tell an admin within one exchange which layer (IDO service, web session, or infrastructure) is the likely culprit, instead of the admin walking through all three by hand.
Frequently asked questions
Why does the smart client time out but the web client does not, or vice versa?
They use different session mechanisms - the smart client depends on the IDO Data Service session timeout, the web client additionally has its own ASP.NET session and IIS app pool idle timeout, so the two can be configured to different effective durations.
Can I set the timeout to never expire?
It is not recommended. Idle IDO sessions consume server resources and, depending on your licensing model, can hold a concurrent session slot. Extend the timeout to a reasonable value instead, such as 30-60 minutes.
Does a VPN disconnect look the same as a session timeout error?
Often yes to the end user, since both produce a 'please log in again' style message. Check whether the timing correlates with VPN idle-disconnect policy before changing SyteLine settings.
Is the CloudSuite session timeout configurable by the customer?
Generally no for the load balancer/ingress layer in hosted CloudSuite environments - that is managed by Infor. Application-level settings you do control should be checked first.
Related
Fixing SyteLine's 'Object reference not set to an instance of an object' error
This is a generic .NET NullReferenceException surfacing through the SyteLine IDO Runtime, not a SyteLine-specific error code. It almost always means a form, script or IDO method referenced a field, row or object that came back null, usually after a customization, a missing related record, or a view/IDO method call before the form finished loading. Turn on detailed client logging and check the most recent customization or form event first.
Error fixResolving SyteLine multi-site replication conflict errors
A replication conflict in SyteLine's multi-site architecture means the same record (commonly an item, customer, or BOM) was changed independently at two sites between replication cycles, and the replication engine could not automatically merge the two versions. Check the replication conflict log first to see which record and which fields collided, then decide which site's version should win before resuming the queue.
Error fixFixing SyteLine's 'transaction out of balance' GL posting error
This posting error means SyteLine tried to create a general ledger journal entry where total debits do not equal total credits, which the GL will not accept. The most frequent causes are a missing or misconfigured account in the automatic account determination setup (COA mapping), currency rounding on multi-currency transactions, or a source transaction (inventory, job cost, AP/AR) that only partially calculated its cost or tax components before posting.
Error fixTroubleshooting SyteLine MRP and APS regeneration that fails or hangs
A SyteLine MRP or APS run that fails to complete, hangs indefinitely, or errors partway through is most often caused by data integrity problems (a BOM loop, an item with an invalid lead time or missing routing), a scheduling engine (APS) process that is stuck or resource-starved, or a concurrent MRP run conflict. Check the MRP/APS log first for the specific item or job it stopped on before assuming it is a system capacity issue.
How-toHow to Run a Cost Rollup in SyteLine
Run Item Cost Rollup from Product Definition > Costing > Cost Rollup, select the site and item range, run it in Simulate mode first to review variances, then run it live to post new standard costs to Item records and the Costed Bill of Material.
How-toHow to Close a Job Order in SyteLine
Close a job order from Production > Job Orders once every routing operation is reported complete and the finished quantity has been received, then run Close Jobs to post the remaining WIP balance to variance and lock the job from further transactions.
AI for ERPAI for Infor SyteLine and CloudSuite Industrial
Add grounded AI to Infor SyteLine or CloudSuite Industrial: natural-language answers, agents over IDOs and ION, on-prem or CloudSuite deployment.
AI for ERPOn-Prem AI for CloudSuite Industrial, Without the Multi-Tenant Cloud Move
Add generative AI to CloudSuite Industrial without moving to Infor's multi-tenant cloud. On-prem private LLM options for CSI, with governance and audit built in.
Stuck on Infor SyteLine (CloudSuite Industrial)?
Talk to engineers who work inside Infor SyteLine (CloudSuite Industrial) every week, and who build private AI that answers these questions from your own ERP data.