Difficulties to use Kontact via WIFI from "Flixbus" and similar servers

Hello Everybody.

At present, I am using Kubuntu 14.04 along with KDE 4.13.3 at an Asus Eee PC 
1025 C - a 32 bits laptop. 

Ever since several months I am getting error reports like this one below when 
using certain public WIFI networks - like the one from "Flixbus":

The server for account "[email protected]" refused the supplied 
username and password. Do you want to go to the settings, have another 
attempt at logging in, or do nothing?

Login failed, server replied: A000004 NO Please log in via your web browser: 
https://support.google.com/mail/accounts/answer/78754 ( Failure ) [ ALERT  ]

From Google, I get in such situation messages that it blocks the log-in attempts; 
they think that it might be some else who has my password. So, every time, 
when I get such a message, I indicate to them that it was really me who tried do 
log in at such a moment. 

When examining the problem more carefully, it becomes clear to me that it still 
is possible to SEND mails via Kontact and the smtp server of Gmail at such a 
public WIFI network. Also this mail is being sent via Kontact. However, retrieving 
new e-mail is only possible via my browser  - not  via Kontact. 

Do some amongst you have any clue how to deal with this problem? Is there any 
"workaround"?

I already have allowed each gmail address I use to work with "less secure apps". 
However, the problem  to retrieve mails via public servers like "Flixbus" (and 
several others) persists. 

Yours.

Bas

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*/Bas G. Roufs/*
Utrecht, NL, EU.
E.: [email protected]; M./SMS: +31 6 446 835 10.
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