I'm not sure I understand what's happening here. For clarification, the support portal account you have is totally separate from the account you use to sign in to the mSecure app. They are different account systems and not tied to one another in any way.
One thing to mention, if you are using mSecure 5 on your various devices, there is no way to download that version of the app any longer. mSecure 6 is the direct upgrade to the older version of the app, so after v6 was uploaded to the App Stores, v5 became unavailable due to how the app stores handle upgrades. I think this may be a moot point, because I checked your account, and it shows the account was upgraded to an mSecure 6 account, so I'm guessing you meant that you are using mSecure 6.
Before we do anything else, can you let me know what happens when you try to open mSecure by entering your password manually on any of your other devices? For example, open mSecure on one of your iOS devices, and don't use Touch ID or turn away from the screen if it has Face ID enabled to unlock the app. Cancel out of the Touch/Face ID UI, then enter your password manually using the iOS keyboard. Are you able to unlock the app on all your other devices by manually entering your password?
Also, please open msecure.com in your web browser, then click "LOGIN" in the top right. Enter your email address and your password. Were you able to sign in to your account on our website?
I have mSecure 5 operating perfectly on several Apple devices. It is great. However, I had to replace the logic board and SDD on a M1 MacBook, so needed to reinstall mSecure5 as it didn't restore correctly from Time Machine. This required me to to Sign In to the Portal, via the App before being able to log in to the database.
I cannot log into the portal via the app as it gives me an invalid username/password error every time. However, I can log into the portal normally with the same credentials, as I have done to create this topic. I believe the problem could be a duplicate account (unlikely & serious security risk), a problem in the app redirect or, most likely, a local cache that I cannot find. I have uninstalled and re-installed several times using Clean My Mac Uninstaller, as I cannot find a mSecure uninstaller, and I notice that it leaves many data and configuration files, plist etc in libraries and elsewhere that need to be cleaned out properly for a re-install to work. I have deleted almost all, but the problem persists. So mSecure 5 does not yet work on this machine.
I have posted a ticket several days ago but still don't have a solution. Advice and fixes welcome!!