In STS/Eclipse go to "project explorer" or "package explorer" and
there is a folder called "server." Open it and you will find server.xml
file. Inside this file at the bottom you find a definition like
<Context docBase="myproject" path="/myproject" reloadable="true"
source="org.eclipse.jst.jee.server:myproject"/>
You might find duplicates of the same definition that you would need to remove.