Hi,
First of all, the error message comes from the C-Find SCP handler which should not be related to a C-Store but who knows what your MRI is doing :-) ?
Third, the error "broken pipe" seems to suggest that the TCP connection has been closed. Since Orthanc complains while acting as a C-Find SCP, it seems that the C-Find SCU (the MRI) has closed the connection too early. This can happen if Orthanc requires a lot of time to answer the C-Find. Again, you should see the time required by Orthanc in the logs.
Then, you might want to increase the SCU timeout on your MRI or you may try to optimize the C-Find execution time by setting the StorageAccessOnFind to Never:
// Performance setting to specify how Orthanc accesses the storage
// area during find operations (C-FIND, /tools/find API route and
// QIDO-RS in dicom-web). Three modes are available: (1) "Always"
// allows Orthanc to read the storage area as soon as it needs an
// information that is not present in its database (slowest mode),
// (2) "Never" prevents Orthanc from accessing the storage area, and
// makes it uses exclusively its database (fastest mode), and (3)
// "Answers" allows Orthanc to read the storage area to generate its
// answers, but not to filter the DICOM resources (balance between
// the two modes). By default, the mode is "Always", which
// corresponds to the behavior of Orthanc <= 1.5.0.
"StorageAccessOnFind" : "Always",
HTH
Alain