How can I check Drupal log files?

If you love the command line, you can also do this using drush with the watchdog show command:

drush ws

More information about this command available here:

https://drushcommands.com/drush-7x/watchdog/watchdog-show/

We can use drush command also to check logs drush watchdog-show it will show recent 10 messages.

or if we want to continue showing logs with more information we can user

drush watchdog-show --tail --full.

MAMP/logs/php_error.log

Above all given option does not work go to the MAMP/logs/ check all type of log-like.

1. mysql_error.log
2. nginx_error.log
3. apache_error.log

For drupal 9, you can access to your logs with drush , here some commands:

• watchdog:delete (wd-del, wd-delete, wd) Delete watchdog log records.
• watchdog:list (wd-list) Interactively filter the watchdog message listing.
• watchdog:show (wd-show, ws) Show watchdog messages.
• watchdog:show-one (wd-one) Show one log record by ID.
• watchdog:tail (wd-tail, wt) Tail watchdog messages.

One more thing if your are not fan with commands, please in the Administrative menu, go to Reports > Recent log messages. On this page is a list of recent log messages which you can filter by type and severity.

but if your are professional you can configure ELK that's will give you all