Patrick, There could be a couple different reasons for the errors, have you looked at the httpd and audit logs? You could just be exhausting the management interface. The preferred max session value is generally based on security requirements, versus automation. Personally for your situation, it sounds like a shorter timeout would be best.
Default session time out for the management interface is 20 minutes. You can view your current settings from the CLI with the following:
root@ve-lab(Active)(/Common)(tmos) list sys httpd all-properties
sys httpd {
allow { All }
auth-name BIG-IP
auth-pam-dashboard-timeout off
auth-pam-idle-timeout 1200
description none
fastcgi-timeout 300
hostname-lookup off
include none
log-level warn
max-clients 10
ssl-certchainfile none
ssl-certfile /etc/httpd/conf/ssl.crt/server.crt
ssl-certkeyfile /etc/httpd/conf/ssl.key/server.key
ssl-ciphersuite ALL:!ADH:!EXPORT:!eNULL:!MD5:!DES:RC4+RSA:+HIGH:+MEDIUM:+LOW:+SSLv2
ssl-include none
}
root@ve-lab(Active)(/Common)(tmos) modify sys httpd auth-pam-idle-timeout 300
root@ve-lab(Active)(/Common)(tmos) save sys config