Failed to update controller's login state after WebServer with PKCE flow

[mguerreiro-vl]

I followed instructions from this page:

https://developer.salesforce.com/docs/atlas.en-us.dataLoader.meta/dataLoader/loader_eca_oauth_pkce.htm

I'm able to authenticate with OAuth Web Server however Data Loader stays put after login (does not close step1 login page and move to insert/update/delete etc).

this is logged in the CMD window:

2025-10-09 11:34:32,628 ERROR [Thread-1] oauth.OAuthFlowHandler handleOAuthLogin (OAuthFlowHandler.java:87) - Failed to update controller's login state after WebServer with PKCE flow
com.sforce.soap.partner.fault.UnexpectedErrorFault
at java.base/jdk.internal.reflect.DirectConstructorHandleAccessor.newInstance(DirectConstructorHandleAccessor.java:62)
at java.base/java.lang.reflect.Constructor.newInstanceWithCaller(Constructor.java:499)
at java.base/java.lang.reflect.ReflectAccess.newInstance(ReflectAccess.java:79)
at java.base/jdk.internal.reflect.ReflectionFactory.newInstance(ReflectionFactory.java:189)
at java.base/java.lang.Class.newInstance(Class.java:715)
at com.sforce.ws.bind.TypeMapper.readSingle(TypeMapper.java:721)
at com.sforce.ws.bind.TypeMapper.readObject(TypeMapper.java:593)
at com.sforce.ws.transport.SoapConnection.parseDetail(SoapConnection.java:250)
at com.sforce.ws.transport.SoapConnection.createException(SoapConnection.java:224)
at com.sforce.ws.transport.SoapConnection.receive(SoapConnection.java:163)
at com.sforce.ws.transport.SoapConnection.send(SoapConnection.java:108)
at com.sforce.soap.partner.PartnerConnection.getUserInfo(PartnerConnection.java:574)
at com.salesforce.dataloader.client.LoginClient.setConfiguredSessionId(LoginClient.java:235)
at com.salesforce.dataloader.client.LoginClient.dologin(LoginClient.java:194)
at com.salesforce.dataloader.client.LoginClient.login(LoginClient.java:135)
at com.salesforce.dataloader.client.LoginClient.connect(LoginClient.java:72)
at com.salesforce.dataloader.controller.Controller.login(Controller.java:272)
at com.salesforce.dataloader.controller.Controller.login(Controller.java:267)
at com.salesforce.dataloader.oauth.OAuthFlowHandler.handleOAuthLogin(OAuthFlowHandler.java:78)
at com.salesforce.dataloader.ui.AuthenticationRunner.loginAsync(AuthenticationRunner.java:108)
at com.salesforce.dataloader.ui.AuthenticationRunner.lambda$login$0(AuthenticationRunner.java:90)
at java.base/java.lang.Thread.run(Thread.java:1474)

this is windows computer. let me know if more information is needed please