Please try 8.5.6 MSI files:
https://www.ritlabs.com/download/the_bat/thebat_32_8-5-6.msi
https://www.ritlabs.com/download/the_bat/thebat_64_8-5-6.msi
Problems of previous versions that arose after sending a message should be resolved in 8.5.6. Please confirm.