Does Websites look wrong or appear differently than they should help? can you give an example link and explain what's not working?

This is what I get:

Login

Authentication Error. Please check email and/or password and try again..

Only on Firefox, not Safari.

RM

So, it's your username/password being wrong. Are you using a saved password? Password manager - Remember, delete and change saved passwords in Firefox

I deleted the old password as you suggested, but am still getting the same message when I try to sign in on Firefox.

Please enter the required information below to continue.

   Authentication Error. Please check email and/or password and try again.

I already have an MLB.com account E-Mail Address: Enter Your Password:

Hello?

HELLO?????????'

This is a forum, responses will be delayed, please be patient.

Did you try the steps and solutions at Websites look wrong or appear differently than they should

This can be caused by corrupted cookies or cookies that aren't send or otherwise blocked.

• https://support.mozilla.org/kb/fix-login-issues-on-websites-require-passwords

Clear the cache and the cookies from sites that cause problems.

"Clear the Cache":

• Firefox > Preferences > Advanced > Network > Cached Web Content: "Clear Now"

"Remove Cookies" from sites causing problems:

• Firefox > Preferences > Privacy > Cookies: "Show Cookies"

• http://kb.mozillazine.org/Cookies
• https://support.mozilla.org/kb/Deleting+cookies

Did it all. No help. Same message.

Start Firefox in Safe Mode to check if one of the extensions (Firefox/Tools > Add-ons > Extensions) or if hardware acceleration is causing the problem (switch to the DEFAULT theme: Firefox/Tools > Add-ons > Appearance).

• Do NOT click the Reset button on the Safe mode start window or otherwise make changes.

• https://support.mozilla.org/kb/Safe+Mode
• https://support.mozilla.org/kb/Troubleshooting+extensions+and+themes

Create a new profile as a test to check if your current profile is causing the problems.

See "Creating a profile":

• https://support.mozilla.org/kb/profile-manager-create-and-remove-firefox-profiles
• http://kb.mozillazine.org/Standard_diagnostic_-_Firefox#Profile_issues

If the new profile works then you can transfer some files from an existing profile to the new profile, but be careful not to copy corrupted files.

• http://kb.mozillazine.org/Transferring_data_to_a_new_profile_-_Firefox