Failed to setup mastodon: missing field access_token

[WordlessEcho]

$ ./mastodon-twitter-sync
Provide the URL of your Mastodon instance, for example https://mastodon.social :
https://lolic.at
Click this link to authorize: https://lolic.at/oauth/authorize<redacted>
Paste the returned authorization code: <redacted>
Error: Failed to setup mastodon account
Because: Http(reqwest::Error { kind: Decode, source: Error("missing field `access_token`", line: 1, column: 31) })
Because: error decoding response body: missing field `access_token` at line 1 column 31
Because: missing field `access_token` at line 1 column 31