How can the Youtube subscription email notification settings be fixed, if I do not see an email from a Youtube channel?

I subscribed to a Youtube channel with the bell notification icon, so I will not miss an email in Gmail. Almost a year later, I have not received any email.

Here is one example. When I subscribe to a Youtube channel such as the Nintendo channel with the bell notification icon, so I will not miss an email in Gmail. Almost a year later, I have not received any email.

Here is another example. When I subscribe to a Youtube channel such as Markiplier with the bell notification icon, so I will not miss an email in Gmail. Two years later, I have not received any email.

Is this really a bug, a glitch, or something else? So, how can the Youtube subscription email notification settings be fixed, if I do not see an email from a Youtube channel?

2017-04-11T00:37:33.809Z