XF 2.1 Login but can't do anything.

[hanyuwomr]

In the home page, I can log in but when I click any thread it auto log out and click login again it shows dialog below.
"Security error occurred. Please press back, refresh the page, and try again. "
I have already truncated table xf_search_index because of it too large and now have this error.
Url forumns : https://vietwriter.com
user test: vuongtu
password: hung@@123
Home page login :

after Login :

Detail Error :

Please help ...
Thanks for all.

 

[Paul B]

I was able to log in without issue.

 

[hanyuwomr]

I was able to log in without issue.

Yes ,U can login but when U click any thread U will logout and didn't do anything .

 

[Paul B]

No problems here - I remain logged in all the time on all pages.

You do have a highly customised site though, with a lot of third party JS and CloudFlare is running, so the usual troubleshooting steps apply - disable all add-ons, revert to a completely default style, remove all custom JS, disable cloudflare and remove any server side caching.

Then re-enable things one at a time until you encounter the problem.