Cannot Recall Master Password

It has been some time since I've used my Mozilla browser and cannot recall what I would have set my master password as. I have tried every password I would have used to no avail. I tried the account recovery with my gmail.com email, but the error message that I keep reaching says that I need the account I would've signed up with? If I enter a completely not related email, I get the proper message that there is no account associated. Being how long it has been, it's not a serious issue to even have access to old credentials, I definitely just want to access my account. Thank you!