Link 1 is the home for US based SmartThings.
Link 2 is the home for EU based SmartThings.
Regardless of where you live you can access both homes. However your phone’s SmartThings app only accesses the one based on where you live. For your specific case your phone app is accessing link 2. You accidentally installed webcore on link 1. This is why your phone can not see it.
To rectify this. You simply have to install again but make sure you are at link 2. Just give it at try even though you think it won’t work.