Server 500 error

My CB site (uses CB subs) was working fine until about 4 days ago. Then, after a frontend login accessing the user list resulted in a HTTP 500 server error. Backend was working without a problem.

I downgraded from PHP v5.4 to v5.3. After that change, I could use all the frontend features without errors. Unfortunately, I discovered the same error resulted after a backend admin login and trying to access CBsubs. After enabling error reporting, I get the following message:

Notice: Undefined offset: 1 in /home2/endodon1/public_html/components/com_comprofiler/plugin/user/plug_cbpaidsubscriptions/plugin/cbsubscontent/cbsubs.content_access.php on line 916

Any suggestions on a remedy? Are there any PHP incompatibilities?

The function that's erroring parses your CBSubs > Plans > PLAN > Integrations > Extensions > By URL Part content. Please check all your plans and ensure you've provided non-SEF URLs that are valid.

Thank for the reply.

I am unable to follow those instructions because I get the error whenever I click on any of the backend CBSub menus. Any suggestions? Why would such an error occur without modifying any variables?

Disable the CBSubs Content plugin within CB > Plugin Management and see if your error persists. If it does not then please ensure you're using the correct version of CBSubs Content for your CBSubs version (ensure both are CBSubs 3.x). If both are up to date re-enable CBSubs Content then review Extensions > Plug-in Manager for Content plugins and disable any 3rd party content plugins then see if issue resolves.

The issue was an outdated "CBSubs Fields Tabs Protect"

I disabled each CB plugin one by one until the page loaded.

That is how I narrowed down the issue.

Then upgraded that plugin and issue was resolved.