(On my PC.) One thing I've noticed is when you are on the "change password" screen and are going to change your password, ER.org asks for your current password and then has you enter your new password twice. It also asks for your email address but says entering it is optional. However, if I try to change my password and do not enter my email address it won't complete the password change. Leaving out your email is not optional, so I enter that twice as well.
OK, so now I've changed my password. Time to test it out. When I log out and attempt to log back in, ER.org is asking for my username and password. Note: It's not asking for my email address and password, it wants my username and password. So I enter my username, Qs Laptop and my password. Success, I'm logged in, works as usual on my PC.
Now if I go to my phone and go to ER.org using the TapaTalk app it looks like I'm logged in as I can get as far as seeing the ER.org listing of the various subforums--FIRE and Money, Life After FIRE, Health and Early Retirement, etc. but if I tap on a subforum to read the posts my phone hangs up and ER.org sends the email stating, "Failed Login Notification". I suspect my phone is attempting to login using my email address, not my username, and that is preventing me from getting logged on with my phone. I will experiment with the TapaTalk app login credentials for ER.org.