This can be solved by going to Chrome browser --> Settings --> Privacy and Security --> Site Settings --> Permissions --> Notifications --> Allow "https://www.tradingview.com".
In case you've already enabled TradingView notifications in Chrome browser, try clicking on the page to activate its sound, especially if you have multiple tabs open. By doing this, it becomes enabled. If this doesn’t correct the issue, then unfortunately, we can't fix this with our efforts as it is defective browser behavior.
However, we can suggest trying to use another browser (i.e. Firefox) as a solution.