pop.gmail.com IPv6 addresses give me "Connection timed out"

Hello,

Since 3 days, when I click on the "Get Messages" button on the Mozilla Thunderbird mail client it takes 5 minutes to connect to pop.gmail.com.

So, in order to understand what happens, I opened a terminal and typed these commands:

Code:$ ping -c 1 pop.gmail.com
PING pop.gmail.com (74.125.140.108) 56(84) bytes of data.
64 bytes from wq-in-f108.1e100.net (74.125.140.108): icmp_seq=1 ttl=110 time=19.2 ms

--- pop.gmail.com ping statistics ---
1 packets transmitted, 1 received, 0% packet loss, time 0ms
rtt min/avg/max/mdev = 19.207/19.207/19.207/0.000 msHere with ping the answer is fast and an IPv4 address is used (74.125.140.108).

Code:$ traceroute pop.gmail.com
traceroute to pop.gmail.com (74.125.140.109), 30 hops max, 60 byte packets
1 192.168.0.254 (192.168.0.254) 0.149 ms 0.359 ms 0.402 ms
2 194.149.164.68 (194.149.164.68) 14.638 ms 14.966 ms 14.353 ms
3 * * *
4 * * *
5 be2151.agr21.par04.atlas.cogentco.com (154.54.61.34) 15.358 ms 15.296 ms 15.255 ms
6 tata.par04.atlas.cogentco.com (130.117.15.70) 14.957 ms 14.380 ms 14.870 ms
7 72.14.212.77 (72.14.212.77) 14.616 ms 19.947 ms 14.275 ms
8 108.170.244.241 (108.170.244.241) 15.451 ms 108.170.244.198 (108.170.244.198) 17.654 ms 108.170.244.176 (108.170.244.176) 14.887 ms
9 209.85.253.217 (209.85.253.217) 16.349 ms 108.170.235.99 (108.170.235.99) 15.896 ms 209.85.255.106 (209.85.255.106) 15.660 ms
10 216.239.48.75 (216.239.48.75) 19.419 ms 216.239.48.37 (216.239.48.37) 19.623 ms 20.057 ms
11 216.239.59.155 (216.239.59.155) 19.667 ms 108.170.231.217 (108.170.231.217) 18.842 ms 216.239.59.155 (216.239.59.155) 19.504 ms
12 209.85.243.85 (209.85.243.85) 20.995 ms 209.85.244.221 (209.85.244.221) 20.239 ms 209.85.241.117 (209.85.241.117) 20.755 ms
13 * * *
14 * * *
15 * * *
16 * * *
17 * * *
18 * * *
19 * * *
20 * * *
21 * * *
22 wq-in-f109.1e100.net (74.125.140.109) 18.901 ms 19.114 ms 19.512 msHere with traceroute the answer is fast and an IPv4 address is used (74.125.140.109).

Code:$ telnet pop.gmail.com 995
Trying 2a00:1450:400c:c08::6d...
telnet: connect to address 2a00:1450:400c:c08::6d: Connection timed out
Trying 2a00:1450:400c:c08::6c...
telnet: connect to address 2a00:1450:400c:c08::6c: Connection timed out
Trying 66.102.1.109...
Connected to pop.gmail.com.
Escape character is '^]'.
Connection closed by foreign host.Here with telnet the answer is slow and two IPv6 addresses are tried first with Connection timed out (2a00:1450:400c:c08::6d and 2a00:1450:400c:c08::6c) then an IPv4 address is used (66.102.1.109).

I guess that Mozilla Thunderbird is doing the same thing than telnet and is trying the IPv6 addresses first.
That could explain why the Mozilla Thunderbird mail client takes 5 minutes to connect to pop.gmail.com.

Do you know how to fix that please?

Thank you.
Best regards.