Your site is trying to load a plugin that doesn't exist.
Code:
Warning: Undefined array key 526 in //libraries/CBLib/CB/Legacy/cbPluginHandler.php on line 866
Warning: Attempt to read property "published" on null in //libraries/CBLib/CB/Legacy/cbPluginHandler.php on line 866
You also had several fields for plugins that don't exist lingering (from CB 1.x days). There was also duplicate cb antispam fields. Both I've cleaned up for you, but am unable to solve your plugin issue as that probably needs to be fixed in your database directly.
I recommend checking _comprofiler_plugin database table for a row with an id of 526 and deleting it. Next check _comprofiler_fields and see if any fields are assigned to that plugin id via pluginid column and likely also need to delete them.
The next issue is as follows.
Code:
Deprecated: explode(): Passing null to parameter #2 ($string) of type string is deprecated in /administrator/components/com_acym/classes/user.php on line 1237
That's coming from AcyMailing.
My guess is there's errors blocking the save process, but it could be something like database limits. You've 142 fields several of which are not in use and recommend deleting any you don't intend on using. For example CB Connect is unpublished and unconfigured so I recommend uninstalling it and deleting its social id fields.