I've not used that marketplace add-on, so only guessing, but since the UI isn't even loading on the timeline tab, I would assume there is an error occurring in the client-side code. If you open the browser dev tools is there an error that shows in the console or on the network tab? If so, that might help track down the issue.
Thanks Ryan, yes it give an error. Also, I reported to Creatio support, because at this time I uninstall the add-on and continue having no Timeline. Here is the error I get on console
Did you tweak any other settings in Timeline (such as adding info about other Creatio objects)? Or did any errors occur when compiling Creatio?
I have reproduced your case, but Timeline has been successfully restored after uninstalling the package. That's why we need more information to investigate this error.
I have forwarded your initial issue with Timeline to the responsible team.