"no data" in graph

[AndreyHammer]

Periodically I get a message "no data" in graphs. After restart Zabbix_server data start to collect again. How to fix this problem?

zabbix version 1.4.4

[Petya]

Please post contents of log files on the agent side
if there are any errors (or strange looking messages) there.

What are the type of items for which zabbix server
stops to receive data? Zabbix agent (Active)?

Similar issue here:

http://www.zabbix.com/forum/showthread.php?t=8718

[AndreyHammer]

SNMPv1 items (Huawei switch). Logging is not enabled on swithch now. I shall try to enable logging and try to find error in logs. May be problem in SNMPv1, and it is necessary to try to use SNMPv2?