HELO/EHLO argument is invalid

Hi,

I have configured the oauth correctly, but when I send a test e-mail I get the following error:

CLIENT -> SERVER: EHLO ~^(.*)$
SMTP -> get_lines(): $data is ""
SMTP -> get_lines(): $str is "501-5.5.4 HELO/EHLO argument "~^(.*)$" invalid, closing connection."
SMTP -> get_lines(): $data is "501-5.5.4 HELO/EHLO argument "~^(.*)$" invalid, closing connection."
SMTP -> get_lines(): $str is "501 5.5.4 https://support.google.com/mail/?p=helo ia7sm104254691wjb.23 - gsmtp"
SERVER -> CLIENT: 501-5.5.4 HELO/EHLO argument "~^(.*)$" invalid, closing connection.501 5.5.4 https://support.google.com/mail/?p=helo ia7sm104254691wjb.23 - gsmtp
SMTP ERROR: EHLO command failed: 501-5.5.4 HELO/EHLO argument "~^(.*)$" invalid, closing connection.501 5.5.4 https://support.google.com/mail/?p=helo ia7sm104254691wjb.23 - gsmtp
CLIENT -> SERVER: HELO ~^(.*)$
SERVER -> CLIENT:
SMTP ERROR: HELO command failed:
SMTP NOTICE: EOF caught while checking if connected
Connection: closed
SMTP Error: Could not connect to SMTP host.
SMTP connect() failed. https://github.com/PHPMailer/PHPMailer/wiki/Troubleshooting

Any suggestion?

Thanks,
Stefano