[SOLVED] Can't obtain license key

Upon upgrading VbSEO to 3.5.2 I got this on the green text field where the license key is supposed to appear:

br bFatal errorb Call to undefined function xcache_isset in bhomecrawlabipublic_htmlvbseoregincclas

I tried to uninstall and reinstall the previous version which worked fine till recently and the same thing happened.

I'm currently using VBulletin 4.0.8 PL1 and checked that the Forum URL field in forum settings was correct.

Any ideas?

Nevermind, disabling custom plugins I managed to find the conflicting one.

We had upgraded our Apache and Php instances this morning on server . The issue maybe caused because of that , however it should be resolved now. Thank you for reporting.