I dug up the password wiki:
re: passwords, it seems the game password is a series of numbers (easily forgotten) that is generated by the app when you first download it and set it up. There does not seem to be a "forgot your password?" doo-hickey to reset the game password if you forget it. Hence Slenderman will tell you (as he told me) to delete the app and re-download it. This will generate a new (string of numbers) password which will be sent by email, but (Slendy assured me) doing this will not affect your account, your present rank, your XP or your fleet of planes. So I did this, and the game app took me through the set-up procedure. At first (horrors!) my rank/plane access seemed reduced/limited, until I hit the "upgrade" (or whatever) button and got the thingy for paying .99 or 4.99. I clicked that and it told me I already purchased it. I clicked through that and after that my rank/plane access was back to normal.
The forum password, in contrast, is chosen by the user and the forum has "forgot your password?" functionality. But unless you set your forum password to be exactly the same as your string-of-numbers game password, well, you know . . .
Bottom line: WRITE 'EM DOWN SOMEWHERES!!!!
Here is another, shorter version of the above:
it sounds like you need to get a new game password, which you probably forgot because it was an auto-generated string of digits. (The game password is different from the forum password which is chosen by the user.) You need to uninstall then reinstall the app. On set up, pick the "existing account" option, feed in the email address you used when you first got the game, and hit "forgot password". It sends you a new one by email. Use that to finish the setup (you will still have your current rank, XP and fleet) and log into the link for joining squads, pick MOM and THEN, finally, you will have the coveted and much-feared MOM tag in-game.