Unable to invite bot, "Could not deserialize events"

[sot-tech]

When trying to invide bot, it does not accept invitation and bridge shows error: Could not deserialize events that were sent to the transactions endpoint see rocketchat.log

Test configuration:

hs_token: "VERYveryLONGsecureRANDOMstringBLAblaBLA"
as_token: "anotherVERYveryLONGsecureRANDOMstringBLAblaBLA"
as_address: "0.0.0.0:8081"
as_url: "http://MAGNESIUM.TEST.LOCAL:8081"
hs_url: "http://NATRIUM.TEST.LOCAL:8008"
hs_domain: "test.local"
sender_localpart: "rc_bot"
database_url: "./db/mrc.sqlite3"
log_level: "debug"
log_to_console: true
log_to_file: true
log_file_path: "/var/log/matrix/rocketchat.log"
accept_remote_invites: false
use_https: false
pkcs12_path: ""
pkcs12_password: ""

#### REGISTRATION ####
id: rc_as
namespaces:
    users:
    - exclusive: true
      regex: '@rcu_.+:test.local'
    aliases:
    - exclusive: true
      regex: '#rcg_.+:test.local'
url: http://MAGNESIUM.TEST.LOCAL:8081
sender_localpart: rc_bot
rate_limited: false

Homeserver: synapse 1.17.0-r0

[exul]

Thank you for the detailed report. The dependencies of the project haven't been updated in a while. The error is probably caused by breaking changes in the Matrix API. Last time I tried to update the dependencies there were too many issues and I didn't have/take the time to fix all of them. Because of that (and other issues, like the bridge using a iron, which hasn't seen much development since quite some time) I've been experimenting with a re-write, but again, didn't have enough time to work on it. I've added the information regarding maintenance to the readme too.