Double hop SQL delegation not working

I've been trying to diagnose this for some time, and unfortunately Im still getting the dreaded anonymous logon issue when trying to connect to a sql db as a domain user.

Steps taken:

App Pool created with delegation service acct
Site / Virtual dir running with Integrated Windows auth only
Made sure site itself can use kerberos KB 215383
Service acct added to IIS_WPG group
Service acct added to "act as part of operating system" under Local Security settings
Service acct added to Log on as service under Local Security Settings
HTTP SPN set for web address + service account (and FQDN)
MSSQLSvc SPN set for sql box and domain acct sql is running as
Trust for delegation turned on service acct, specified services, and sql service acct

After all this, Im still getting the exact same error from when I started. Login failed for user 'NT AUTHORITY\ANONYMOUS LOGON'. This has advanced my balding by at least 5 years so far. I would greatly appreciate any additional tips on diagnosing or setting up.

Solution

Turns out using setspn -L found some conflicts with a service acct. Using setspn -D to get rid of those conflicts fixed the issue.

First time doing this, Kerberos is very picky! And as always, thank you SO Community