Ask Analysis-one why their log-in doesn't work without Flash Player. It's their website, they need to update it. There's nothing you can do from your end.
Given that Internet Explorer 6.0, Firefox 2.0 and Adobe Flash Player v9 have not existed for a very, very l-o-n-g time, I don't have much confidence in that site or the people running it.
All websites had 3-1/2 years advanced notice that Flash Player was ending on Dec 31, 2020, more than ample time to change their log-in system before now.
https://www.adobe.com/products/flashplayer/enterprise-end-of-life.html
Also for your own protection, please DO NOT post email or other personal information in this public user-to-user forum where scammers, spammers or robot harvesters could exploit it.