error 500

william5900, could you attach /plugins/system/mobilebot.php that you have on your server? Look like it is damaged. I'd recommend you to backup:
1) administrator/components/com_mobilejoomla/config.php file (it contains all MJ settings)
2) probably template files (if they were modified)
3) positions where Select Markup module is published,
then uninstall MobileJoomla, check that you have sufficient free disk space, install MobileJoomla, and restore backup data.

Hi William.

I understand you have server 500 error using Mobile Joomla. We need the following information in order for us to resolve this issue:

- error_log file - This is located in your root directory or your main joomla directory.

Please send the error_log file to our email support​@​mobilejoomla.com.

Best,

John Mark C.
Mobile Joomla! Support