Email authentication
Disable it. That’s probably the only way. The reason it may be prompting it every time is because the IP you’re connecting from likely changes quickly.
It will learn your IP range over time and it will not be that much of an issue once that occurs. That is unless you are connecting from different ISPs/locations regularly. Disabling email authentication puts your account at significant risk and you will need to contact support to do so. Would you rather deal with email authentication or have to deal with contacting support if your is account hacked, all your stuff is gone, and your account got banned because the hacker used your account to sell gold or bot? Then you will have to go through the whole process of proving ownership of the account, getting a roll back and all sorts of things that are not fun for people that have had their accounts hacked.
If it is a continued problem you may consider using the mobile authenticator if you have a phone that allows it.
Here is a thread for further reading:
https://forum-en.gw2archive.eu/forum/support/support/Disable-Email-Authentication/first#post4183631
(edited by JustTrogdor.7892)