You may use alternative way to backup/forward/download your email in your Gmail as per below steps:

1. Log into your Gmail account.

2. Access to the Gmail Setting.

gmail settings

3. Select on the :Accounts and Import tab”.

4. Click on the “Add a POP3 mail account you own” in the POP3 section.

add a pop3

5. Enter your email and hit Next Step button.

add a email account you own

6. Enter your information by refer to below example:

Username: Your full email address
Password: Your email account Password
POP server: (where should replace with your domain name)
Port: 110


7. Click “Add Account” to add your account.

settings a mail account you own