TypeError: Cannot read properties of undefined (reading 'joinContract')

[jahnavi1415]

Source
views\HeaderMenu.js (98:29) @ Object.onClick

96 | handleJoinClicked = () => {
97 | var publicKeyBuffer = this.account.getPublicKeyBuffer();

98 | this.contractManager.joinContract(publicKeyBuffer, (resultEvent) => {
| ^
99 | if (resultEvent == Constant.EVENT.ON_REJECTED || resultEvent == Constant.EVENT.ON_ERROR) {
100 | this.setState({isJoinButtonLoading: false});