Issue Description:
I have a non-standard setup that uses MySQL and an external web server that is hosted on a different box. I think its safe to assume that my setup its self is most like configured correctly because everything including marker updates, render data, and registration codes are working properly. However, it appears that once you register an account on dynmap, your login credentials are NOT saved. As a result, whenever you later try to log out and log back in, it does not work!

• Dynmap Version: v3.4 (LATEST)

• Server Version: Paper Spigot 1.12.2

• Pastebin of Configuration.txt: https://pastebin.com/5SETL3z2*](https://pastebin.com/FhMKyJr4

• Server Host (if applicable): Self Hosted

• Pastebin of crashlogs or other relevant logs:
  

• Other Relevant Data/Screenshots: https://youtu.be/LyIvd9eUaAU

• Steps to Replicate:

1. Follow the wiki to setup an external webserver with MySQL (https://github.com/webbukkit/dynmap/wiki/%5BTutorial%5D-Setting-up-a-standalone-web-server-with-MySQL-SQLite/)
2. Try to register an account

[X] I have looked at all other issues and this is not a duplicate
[X] I have been able to replicate this

I was mistaken that this is a dynmap issue when in reality, the issue was, after moving to MySQL, I deleted the webauth.txt file (didn't realize it was still needed). So I thought this was caused my MySQL.