sorry took so long to respond, this post was corrupted. Are you not able to use the sponsor portal? the manage accounts shouldn't be used as its limited. also need to make sure DNS and certificates resolve correctly. are you going through NAT firewall?
https://www.cisco.com/c/en/us/td/docs/security/ise/2-6/admin_guide/b_ise_admin_guide_26/b_ise_admin_guide_26_chapter_01111.html#id_35332__ul_zkl_vpx_twI would recommend setting up easy URL FQDN access to sponsor portal to use it that way as well
https://www.cisco.com/c/en/us/td/docs/security/ise/2-4/admin_guide/b_ise_admin_guide_24/b_ise_admin_guide_24_new_chapter_011100.htmlFully Qualified Domain Name (FQDN)—Enter at least one unique FQDN and/or hostname for your Sponsor or MyDevices portal. For example, you can entersponsorportal.yourcompany.com,sponsor, so that when the user enters either of those into a browser, the sponsor portal displays. Separate names with commas, but do not include spaces between entries.
If you change the default FQDN, then also do the following:
Update your DNS so that the FQDN of the new URL resolves to a valid Policy Services Node (PSN) IP address. Optionally, this address could point to a load balancer virtual IP address that serves a pool of PSNs.
To avoid certificate warning messages due to name mismatches, include the FQDN of the customized URL, or a wildcard, in the subject alternative name (SAN) attribute of the local server certificate of the Cisco ISE PSN.