Adding Joomla! Tags to Event Categories in Backend Admin

When saving a category with a Joomla! tag ( selected from tag dropdown on right hand side), I'm getting the error :
"Error Save failed with the following error:".

Have latest version of joomla, 3.6.2 fresh install of jevents 3.4.20 , every plugin etc. up to date.
Also checked the tag databases in my joomla install match the joomla installation scheme, all ok.


<code>
PHP Version : 5.6.18
MySQL Version : 5.5.40-MariaDB-cll-lve
Server Information : Linux cloud02.smarthosting.co.uk 2.6.32-604.30.3.lve1.3.63.el6.x86_64 #1 SMP Sun Sep 27 06:34:10 EDT 2015 x86_64
Fix jQuery? : Yes
Load JEvents Bootstrap CSS? : No
Club code set? : No
User Agent : Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/53.0.2785.116 Safari/537.36
Joomla : 3.6.2
component_com_jevents : 3.4.20
component_com_jce : 2.5.27
component_plg_kunena_comprofiler : 5.0.2
component_com_acymailing : 5.5.0
module_mod_acymailing : 3.7.0
module_mod_jevents_cal : 3.4.20
module_mod_jevents_custom : 3.4.20
module_mod_jevents_filter : 3.4.20
module_mod_jevents_latest : 3.4.20
module_mod_jevents_legend : 3.4.20
module_mod_jevents_switchview : 3.4.20
plugin_acymailing_contentplugin : 3.7.0
plugin_acymailing_kunena_j30 : 3.0.0 (not enabled)
plugin_acymailing_managetext : 1.0.0
plugin_acymailing_newsfeeds_j30 : 1.0.0 (not enabled)
plugin_acymailing_online : 3.7.0
plugin_acymailing_share : 1.0.0
plugin_acymailing_stats : 3.7.0
plugin_acymailing_tablecontents : 1.0.0
plugin_acymailing_tagcontent : 3.7.0
plugin_acymailing_tagsubscriber : 5.5.0
plugin_acymailing_tagsubscription : 5.5.0
plugin_acymailing_tagtime : 5.5.0
plugin_acymailing_taguser : 5.5.0
plugin_acymailing_template : 5.5.0
plugin_content_acycontent_j30 : 1.0.0 (not enabled)
plugin_content_jevents : 3.4.20
plugin_editors_acyeditor : 5.5.0
plugin_finder_jevents : 3.4.20 (not enabled)
plugin_kunena_comprofiler : 5.0.2 (not enabled)
plugin_search_eventsearch : 3.4.20
plugin_system_acymailingtoolbox_j30 : 1.0.0 (not enabled)
plugin_system_gwejson : 3.4.20
</code>


Any ideas on what to check for next?

Thanks in advance,
Steve.