Dear Octo WoW.
Seems there are tons of issues specially with when you play you got disconnected and cannot login at all but server is online, after some time you can login again and got disconnected again.
What is problems:
1) Your WoW.exe is corrupted and Cannot be used ( Plus Defenders block it cause of virus even add exception not works on it cause its not correct or need to be rebuilded .exe) - If i take from Turtle wow the wow.exe im able to connect without issues no antivirus no error nothing, so your wow.exe has something not ok.
2) Why it has this random disconnections (no lag or latency issues) game works smoothly but cannot play long. Client is your original with launcher
3) Your launcher crashed gives Update (but cannot update anymore) if you click update or recheck verify files nothing happens
4) Website validation of emails function not work check your SMTP settings or website codes or Traffic allow on hosting not to have blacklist filters or something to block transfer, mostly you can check with hosting they can detect the issue with emails