Post SMTP Error

Our WordPress site is no longer able to send out emails.
When I run a Send Test email, I get this error in the log
Status: 5.7.139 Authentication unsuccessful, account locked. Contact your administrator. [SJ0PR13CA0096.namprd13.prod.outlook.com]
Solution: Check you credentials, wrong email or password.

However, I’ve checked the log in credentials and they are correct.

From the Diagnostic Test, I get this readout:

Mailer: postsmtp
HostName: venetoviews.org
cURL Version: 7.85.0
OpenSSL Version: OpenSSL/1.1.1n
OS: Linux pool115-210-29.bur.atomicsites.net 4.19.0-21-amd64 #1 SMP Debian 4.19.249-2 (2022-06-30) x86_64
PHP: Linux 7.4.32 en_US.UTF-8
PHP Dependencies: iconv=Yes, spl_autoload=Yes, openssl=Yes, sockets=Yes, allow_url_fopen=Yes, mcrypt=Yes, zlib_encode=Yes
WordPress: 6.1 en_US UTF-8
WordPress Theme: Redhill
WordPress Plugins: Akismet Anti-Spam, AMP, CoBlocks, Easy Smooth Scroll Links, WordPress.com Editing Toolkit, Gutenberg, Jetpack, Layout Grid, Modern Events Calendar, Page Optimize, Post SMTP, WP-Members
WordPress wp_mail Owner: /srv/htdocs/wp-content/plugins/post-smtp/Postman/PostmanWpMailBinder.php
WordPress wp_mail Filter(s): wp_staticize_emoji_for_email, PostsmtpMailer->get_mail_args
WordPress phpmailer_init Action(s): atomic_enableSMTP, atomic_add_mail_tracking_header, PostsmtpMailer->phpmailer_smtp_init
Postman: 2.1.10
Postman Sender Domain (Envelope|Message): state.gov | state.gov
Postman Prevent Message Sender Override (Email|Name): No | No
Postman Active Transport: SMTP (smtp:tls:login://smtp-mail.outlook.com:587)
Postman Active Transport Status (Ready|Connected): Yes | Yes
Postman Deliveries (Success|Fail): 16256 | 2026

Any advise for a Novice WordPress user.

The page I need help with: [log in to see the link]