JIRA no longer allowing me to assign tickets to individuals

[Laura Abney]

All of a sudden I'm no longer able to assign tickets to group members that I've been assigning tickets to for over a year.  It tells me that they do not exist.  I can assign to 2 other administrators, but not all of the administrators any more.  How can I get this fixed?

[Chozo]

I don't know if I get your problem, but try to check permission schemes on the project and user roles (groups etc.) , if something didnt changes.

[Laura Abney]

I've checked all of the permissions and everyone still has their permissions and the group development files look fine.  Reboots have not resolved in over a week of attempting.  We had an update, however, this problem wasn't an issue right after the update but 2 weeks later.  Prior to last week I could assign issues to either administrators or users, now only 3 of the administrators can be assigned and none of the users will show up.  

[Deleted user]

I have this sometimes when the network flaps or the active directory lags. If it doesn't resolve itself in a few minutes, restarting the jira instances usually solves it