ParseError syntax error, unexpected 'EnvironmentInterface' (T_STRING), expecting function (T_FUNCTION)

[putrageass]

Hi there, I'm a new user for Laravel, currently still learning.
I just recently upgrade my Laravel app which I used for Loan Device Management, from 7.2 to 8.0

Everything went great except I can't send any notification anymore using email on my local file.

The error is
ParseError
syntax error, unexpected 'EnvironmentInterface' (T_STRING), expecting function (T_FUNCTION) or const (T_CONST)

Is it because the PHP version? currently I'm using PHP 8 on my local.

I already search it on google but no luck, I'm aware about Markdown parse problem, but can't get around this problem.