After installing the plugin, neither cms nor ftp works, what should I do?

Question

CMS

There is a site on joomla 1.5, the task was to make micro-markup, for this I installed the j4schema plugin, and after starting the installation, neither CMS nor FTP nor the site opened, but when opened via VPN, everything works, except for the CMS admin panel, but with all this, the admin panel opens from the phone (also with VPN). Computers changed, the Internet too. Tell me what could be the problem?

Answer 1

If it is not possible to connect to ftp and the provider is out of business, then Joomla is even more so. Write to the host.
If the admin panel opens somewhere, somewhere it doesn’t - the matter may be in the presence / absence of the necessary cookies on the device. Try to clean them where it won't open.
What is meant by "does not open"? What error does it show? What are the errors in the logs?
As for everything else, you can guess. Maybe your version of php is too old, or somewhere you open with www, somewhere without (Joomla has a jump on this).