slackbot:20: error: invalid operands of types 'const char [39]' and 'const char [43]' to binary 'operator+'

 #define SLACK_BOT_TOKEN "xoxb-111111111111-abcdefghijklmnopqrstuvwx" // Get token by creating new bot integration at https://my.slack.com/services/new/bot 

                         ^

C:\Users\work\Desktop\arduino-slack-bot-master\arduino-slack-bot-master\slackbot\slackbot.ino:177:57: note: in expansion of macro 'SLACK_BOT_TOKEN'

   http.begin("https://slack.com/api/rtm.start?token=" + SLACK_BOT_TOKEN, SLACK_SSL_FINGERPRINT);

                                                         ^

exit status 1
invalid operands of types 'const char [39]' and 'const char [43]' to binary 'operator+'

  http.begin("https://slack.com/api/rtm.start?token=" + SLACK_BOT_TOKEN);

#define SLACK_SSL_FINGERPRINT "AB F0 5B A9 1A E0 AE 5F CE 32 2E 7C 66 67 49 EC DD 6D 6A 38" // If Slack changes their SSL fingerprint, you would need to update this

  http.begin("https://slack.com/api/rtm.start?token=" + SLACK_BOT_TOKEN, SLACK_SSL_FINGERPRINT);