The version of 1 QQ is too low, resulting in the failure to modify the signature.

2. The network is not smooth, which leads to the failure of signature modification.

3. The modified signature contains special characters, so the system cannot display it.

You can solve this problem by upgrading QQ.

QQ upgrade:

1. Go to im.qq.com, the official website of QQ, and click Download.

2. Jump to the download page and find the QQ client for PC.

3. Click Download and wait for the installation package to be downloaded locally.

4. Click the downloaded installation package for a new installation to complete the update.

5.QQ upgrade is completed.