Finally Resolved

I reviewed my email this morning as it is something I have struggled with in recent times. The prompt to actually review the email was the need to locate the email for a book I got a few days ago.
While looking through the mail, I got an email from Jetpack about the observation that one of my WP plugins which I got early on had issues which made it vulnerable to remote attacks.
I looked at the plugin (WPBakery plugin version older than 6.4.1) and decided that with the design of the new wordpress system, it was no longer required.
I uninstalled the plugin and that was it.
A few minutes later I asked myself, could that be the reason I struggled to log-in using MarsEdit? I fired up the app and did a sync and behold the app synced and I got the latest update from the site.
This has been bugging me for a while and my next plan was to do a systematic elimination of the plugins.
This sync issue had consumed hours of troubleshooting but with no solution.
Glad that is over and done with!
This cleared all my third-party app sync issues with the website which is a relief indeed as it is a much faster way to post to and update posts on the website.