only pages with "default template" are invisible

What happened just before this? Added a plugin? Edited something? Host had a power failure? Host upgraded software or hardware?

Try to switch to another theme and then back again.

Disable all of your plugins.

Look for an .htaccess file and rename it if you find it.

Don’t confuse not seeing an error with not getting an error. Security conscious servers will hide errors. Do you have access to your server’s error logs?

Try putting define('WP_DEBUG',true); in your wp-config.php file. You might see some warnings and errors.

What happened just before this? Added a plugin? Edited something? Host had a power failure? Host upgraded software or hardware?
> The only thing that has happen is an exceed of the maximum server space.

Try to switch to another theme and then back again.
> already done, no result

Disable all of your plugins.
> already done, no result

Look for an .htaccess file and rename it if you find it.
> i will test that
> ! done the test with renaming the .htaccess file, no result.

Don’t confuse not seeing an error with not getting an error. Security conscious servers will hide errors. Do you have access to your server’s error logs?
> no, but server administrator doesn’t find errors either

Try putting define(‘WP_DEBUG’,true); in your wp-config.php file. You might see some warnings and errors.
> already done, no result, nothing at all

> What now? Thanks for more help.

I have find a weird hidden symbol in de code in the page.php file.
This wasn’t giving an error but gives “blank” pages.
Website works again.
fixed. thanks.