The guild chat bug seems to be only happening when there is a pet event that is triggered.
I remember being able to write in chat yesterday and ya I think when I had triggered 3 pet event I was no longer able to chat during that time.
But because today was pet event 24h, the chat bug was going on the whole day.
Thanks Maxthor. Does it happen when you try to “Connect” to chat or just if you try to send a message?
Hello @Cyrup
When I click on the chat icon and then click yes, the spinning wheel appears and will load forever.
To get the spinning wheel disappear I have to hit the “back” button on my phone.
After that I have access to chat and I can send a message on global chat. But when type a message on guild chat and click “ok” the message is not showing up, although I can see any previous message from guildmate.
Ok I can send message In guild chat if:
I click the chat icon and click the yes button
I hit the return button( the back arrow) on my phone after minimizing the game
Click the chat icon again
Type something in the guild chat
Click on the global chat tab
Click on guild chat tab again
Voilà I now see the message I had typed earlier
I have closed and reopened the game and did the same manipulation I have describe above and unfortunately it didn’t worked this time
Hey all experiencing chat issuues
We believe we may have fixed the problem. Please completely close/reopen your game and verify integrity of game cache if you are on Steam and experiencing issues.
Let me know how this goes.
Definitely not working on Android.
I still had the spinning wheel and had to minimize and hit back arrow to even get in chat tab.
In 1 min the chat might be fixed because the pet event will be ending hmmm
Tried to manually fix your chat, please restart and let me know how this goes (might only fix guild only)
Nvm still not working as of right now.
oO now it is working, at this very second.
Thanks @Cyrup
i am magic !
I can confirm that this seems to have worked for me.
Chat still not working for me on iOS 
Same here! I hope my guildies who aren’t in our LINE chat know I am not just ignoring them
Only read the OP, but I’m experiencing the exact same issue.
With limited time to actually spend on playing, waiting a bazillion hours for a match to load, only for me to close it in frustration is extremely poor and my guild suffers now too. 
Too much time spent on BS such as ‘pets’ which don’t add any value at all to gameplay experience and (what appears to be) zero time spent on operational stability…
Try this:
Click on chat icon
Join channel 001
Join Channel 002
Join Channel 001
Restart the game
Click in guild chat tab