SAML Authentication successes at first but failed with weird characters added in the path

Hi all, 

I added a SAML config like this

The test successed at first

However,  the second time I test the config, the url would add unknown icons after the correct path automatically, which may cause the reason 401.

Could you please give any advises and solutions?

By the way, I couldn't find the pages where users could choose their login page:

Do you have any ideas?

Thanks a lot!