Now I see the reason:
https://support.google.com/cloud/answer/10311615#zippy=%2Ctesting
"""
Authorizations by a test user will expire seven days from the time of consent. If your OAuth client requests an offline access type and receives a refresh token, that token will also expire.
"""
After I configured xoauth2 and it worked, now I get above message.
What can I do?
| Sysop: | Keyop |
|---|---|
| Location: | Huddersfield, West Yorkshire, UK |
| Users: | 715 |
| Nodes: | 16 (2 / 14) |
| Uptime: | 151:52:57 |
| Calls: | 12,091 |
| Calls today: | 4 |
| Files: | 15,000 |
| Messages: | 6,517,621 |