Your package synapse failed to build from source in current F28. https://koji.fedoraproject.org/koji/taskinfo?taskID=24878563 For details on mass rebuild see https://fedoraproject.org/wiki/Fedora_28_Mass_Rebuild
Needs synapse 0.2.99.3 + vala 0.40.3 (there is also vala side bug fixed in 0.40.3)
F-29 build now successful with vala-0.40.3-1.fc29 and synapse-0.2.99.4-1.fc29. Will do F-28 build when vala 0.40.3 hits on F-28.
synapse-0.2.99.4-1.fc28 has been submitted as an update to Fedora 28. https://bodhi.fedoraproject.org/updates/FEDORA-2018-6dbe7a2155
synapse-0.2.99.4-1.fc28 has been pushed to the Fedora 28 testing repository. If problems still persist, please make note of it in this bug report. See https://fedoraproject.org/wiki/QA:Updates_Testing for instructions on how to install test updates. You can provide feedback for this update here: https://bodhi.fedoraproject.org/updates/FEDORA-2018-6dbe7a2155
synapse-0.2.99.4-1.fc28 has been pushed to the Fedora 28 stable repository. If problems still persist, please make note of it in this bug report.