What did you do before this error occured?
It’s seems like you updated from an older version (lower than 2.7.0) of MODx and the column alias_visible wasn’t added to the database table on the update.
You could try adding this missing column manually (for example in phpMyAdmin ) with the following SQL statement from this github issue.
ALTER TABLE `modx_site_content` ADD `alias_visible` TINYINT( 1 ) UNSIGNED NOT NULL DEFAULT '1' AFTER `alias` ;
opened 08:52AM - 28 Jun 20 UTC
closed 06:53AM - 29 Jun 20 UTC
## Bug report
### Summary
After a gradual update of СMS from version:
2.5.5 -… > 2.6.0 -> 2.6.5 -> 2.7.0 -> 2.7.3 an error appeared in the journal and the admin panel stopped working. White screen.
### Observed behavior
Update 2.5.5 -> 2.6.0 -> 2.6.5 -> 2.7.0 -> 2.7.3
``` php
[2020-06-22 13:59:47] (ERROR @ /home/egg00/***/www/core/xpdo/om/xpdoobject.class.php : 240) Error 42S22 executing statement:
Array
(
[0] => 42S22
[1] => 1054
[2] => Unknown column 'modResource.alias_visible' in 'field list'
)
[2020-06-22 13:59:47] (ERROR @ /home/egg00/***/www/core/xpdo/om/xpdoobject.class.php : 240) Error 42S22 executing statement:
Array
(
[0] => 42S22
[1] => 1054
[2] => Unknown column 'modDocument.alias_visible' in 'field list'
)
```
### Expected behavior
I took the advice and fulfilled the SQL request and it worked.
```sql
ALTER TABLE `modx_site_content` ADD `alias_visible` TINYINT( 1 ) UNSIGNED NOT NULL DEFAULT '1' AFTER `alias` ;
```
https://github.com/modxcms/revolution/issues/14219#issuecomment-450200690
### Related issue(s)/PR(s)
#15035
### Environment
MODX 2.7.3, apache, mysql 5.7.16-10, php 7.2.31