1) start my external jboss running teiid 8.6 and my teiid instance within the designer
2) create a teiid model project
3) import a salesforce model
4) supply un, pw, and url
5) test connection...
6) select a table from the model, e.g., Account
6) select preview data

See exception
EIID70006 {"JBAS014671: Failed services" => {"jboss.ra.deployment.PREVIEW_7ca3b12a-7296-455f-a6a3-2ccc75fd3819_SFTest_SFTestModel_1" => "org.jboss.msc.service.StartException in service jboss.ra.deployment.PREVIEW_7ca3b12a-7296-455f-a6a3-2ccc75fd3819_SFTest_SFTestModel_1: org.jboss.msc.service.StartException in anonymous service: JBAS010446: Failed to start RA deployment [PREVIEW_7ca3b12a-7296-455f-a6a3-2ccc75fd3819_SFTest_SFTestModel]
Caused by: org.jboss.msc.service.StartException in anonymous service: JBAS010446: Failed to start RA deployment [PREVIEW_7ca3b12a-7296-455f-a6a3-2ccc75fd3819_SFTest_SFTestModel]
Caused by: org.jboss.jca.deployers.common.DeployException: IJ020060: Unable to inject: org.teiid.resource.adapter.salesforce.SalesForceManagedConnectionFactory property: url value: https://cs30.salesforce.com/services/Soap/u/29.0"}}

The issue I see is the URL property "name" needs to be uppercase.