google webmaster - access denied 403

[kyomar]

Hi, I am getting suddenly many 403 access denied crawl errors. The links are all okay and robots[dot]txt seems to be okay as well. I haven't changed anything in a while so I am confused what could cause this crawl errors. I am running 4.5 rev1894.
Thank you for your time!

[datahell]

See defender's security log to find out why you get forbidden errors. Mostly this is due to malformed urls on site.

[kyomar]

Thanks a lot datahell for your quick response. I have checked the security log but I am not sure what and where to look for. I found "defender bans" and "security" logs. Which one is the defender's security log? I checked the error log as well and only 404 errors are listed.
Thank you and have a nice weekend!