In Thunderbird if you get the message that your inbox is full and you cannot receive any more new emails you need to compact your folders.
Don't try to delete your mails, you can delete complete inbox and still get the same message.
Go to File/Compact folders
If you have imported your passwords to Chrome you may notice that on some websites they will not appear autofilled. This most probably happened if the URL in question is not recognized by Chrome for some reason, but still it being present in the list will prevent Chrome to offer to save password when you enter it.
Go to: Settings/Show advanced settings Privacy/Manage saved passwords
Find the website and delete the password/site.
Type the correct URL and username/password, when Chrome asks to save it accept.
The password should appear autofilled next time you visit the site.