Try to set the Redirect URI at your Identity Client in OneIM to your load balancer (DNS) based Url of the portal.

Appreciate your response

The redirect URI is set to DNS based URL only, any other possible cause?

What Browser are you using, Including the version?

You could, in addition, try to change the web.config of the Web Portal and change the line

<httpCookies requireSSL="true" sameSite="Strict" />

to

<httpCookies requireSSL="true" />

and check if it works then.

I already changed 

httpCookies requireSSL="true" sameSite="Strict" />

to

<httpCookies requireSSL="true" />

the situation improved a little but still it is not resolved completely 

when i enter my URL https://mywebportal, it first redirects to  https://mywebportal/IdentityManager and it gives the same error too many redirects. if i remove the /identityManager from the URL and again hit enter it works fine and take me to login page of IDP

Chrome : Version 85.0.4183.102 (Official Build) (64-bit)

IE Version 11.1457

Thanks,

Pranav

I already changed 

httpCookies requireSSL="true" sameSite="Strict" />

to

<httpCookies requireSSL="true" />

the situation improved a little but still it is not resolved completely 

when i enter my URL https://mywebportal, it first redirects to  https://mywebportal/IdentityManager and it gives the same error too many redirects. if i remove the /identityManager from the URL and again hit enter it works fine and take me to login page of IDP

Chrome : Version 85.0.4183.102 (Official Build) (64-bit)

IE Version 11.1457

Thanks,

Pranav

Hello Markus,

Also i read in one of your previous post that we need to specify the base URL in web.config document to DNS URL. In my current configuration it is pointing to webserverURL/IdentityManager.

Do i need to change this also to DNS/IdentityManager URL

You could try to change the BASEURLs as described to the URL (https://mywebportal) where you want to access the portal to see if that helps. To get more information about the error you could check the log of the Web Portal turned to Debug level.