I know this has been posted ad nausem. Well, equally tiresome is that Adobe, after years of this issue being reported, hasn't solved it. And their lame abnegation of the issue with these finger-pointing excuses about Windows credential manager or internet security programs being at fault is pathetic.
Your software is the ONLY program that has ever had this issue, and it's continued like this for something like 4 years now. Every other day: SIGN IN, SIGN IN. Every program. And none of these solutions Adobe posts work. Figure it out. It's your software causing the issue.
This is a public forum with "some" Adobe staff participation, use the link below to make a report or request
-for Video & Audio & Animator programs https://adobe-video.uservoice.com/
-for PPro https://adobe-video.uservoice.com/forums/911233-premiere-pro
-https://www.adobe.com/products/wishform.html for everything else
I have no such problems. So it's not a widespread problem. Perhaps you have a permissions problem on your end. Which operating system do you have?
Hilarious, that the responses here are asking me to point to threads which tell you to do the things I've already done repeatedly. And yes, this is indeed a "widespread issue." Take a look on google at how many discussions exist about it, for years.
It's most likely caused by your anti-virus or firewall software. See link below.
If you continue to have problems, contact Adobe Support for technical assistance.
CONTACT ADOBE SUPPORT:
Online Chat: https://helpx.adobe.com/contact.html?rghtup=autoOpen
Phone M-F, during normal business hours: https://helpx.adobe.com/contact/phone.html