Symptoms
Unable to log into Horde webmail from a particular email account:
A fatal error has occurred Horde_Prefs_Scope::serialize() must return a string or NULL
Details have been logged for the administrator
Cause
JSON string in Horde database is corrupted. For example, it contains a Unicode character(s).
Resolution
-
Backup
horde
database:For Linux:
# plesk db dump horde > horde.$(date +%F_%R).sql
For Windows:
plesk db dump horde > C:horde_dump.sql
-
Delete all entries from
horde_prefs
table that are related to the affected email account:Warning: This will delete configurations that were set in Horde UI for this user and they should be recreated anew.
Note: Replace
[email protected]
with the affected email account name.# plesk db “DELETE FROM horde.horde_prefs WHERE
pref_uid
= ‘[email protected]’;”