Very often when I try to create a new iPrint printer in iManager I get the following error message:
Error: Create Printer Failure
Request (SERVER_ERROR) - bad status code (0x500)
IPP Error: 0x500

The iPrint Manager logfile has the following error:
Error (-672) was returned, Operation modify.

I use the same server for iPrint and iManager. The server has a read/write replica of [ROOT], the only partition in the tree.

A restart of Apache/TomCat/iPrint manager does not solve the problem.