I was recently configuring an ASA running 8.x software to authenticate and download ACL’s for remote-access users from microsoft IAS. During my testing I changed one of the ACE’s but accidentally used incorrect syntax (tried to match a port number on an “ip” access list):

ip:inacl#100=permit ip 10.1.0.0 255.255.255.0 host 10.2.0.1 eq 3389

Which should have read

ip:inacl#100=permit tcp 10.1.0.0 255.255.255.0 host 10.2.0.1 eq 3389

The end result was that my authentication denied and I received this error on the ASA:

%ASA-3-109032: Unable to install ACL ‘AAA-user-username-ABC12345’, downloaded for user username; Error in ACE: ‘permit ip 10.1.0.0 255.255.255.0 host 10.2.0.1 eq 3389’

No biggie, fixed the syntax and tried to logon again. But then I recieved this interesting error:
%ASA-4-716023: Group <groupName> User <username> IP <x.x.x.x> Session could not be established: session limit of 2 reached.
%ASA-4-716007: Group <groupName> User <username> IP <x.x.x.x> WebVPN Unable to create session

I thought maybe I had some previous sessions still connected:

ASA# sh uauth
Current    Most Seen
Authenticated Users       0          1
Authen In Progress        0          0

ASA# sh vpn-sessiondb webvpn
INFO: There are presently no active sessions of the type specified

It appears that if a SSLvpn connection fails due to an incorrectly configured downloadable ACE it locks out that session. I couldn’t find a command that would return the sessions back to the available pool and had to reload the ASA to correct it.

Now I doubt you would see this issue in a production environment but if anyone knows of a way to correct this without reloading I would love to know.