Note that while the + character is absolutely legal in email addresses there are lots of mail filters out there that won't let it pass.
Your address is similar but has more or fewer dots (.) or different capitalization.
Sometimes you may receive a message sent to an address that looks like yours but has a different number or arrangement of periods. While we know it might be unnerving if you think someone else's mail is being routed to your account, don't worry: both of these addresses are yours.
Gmail doesn't recognize dots as characters within usernames, you can add or remove the dots from a Gmail address without changing the actual destination address; they'll all go to your inbox, and only yours. In short:
[email protected] = [email protected]
[email protected] = [email protected]
[email protected] = [email protected]
All these addresses belong to the same person. You can see this if you try to sign in with your username, but adding or removing a dot from it. You'll still go to your account.