I'm Getting MySql max_connect_error, but Max_used_connections shows it didn't reach the limit

From time to time, I'm getting an error "

(): (HY000/1203): User already has more than 'max_user_connections' active connections.

" I checked the MySQL max_connection variable, and it's at 150. What's odd is that when I check for Max_used_connections, it says 41, which (I think) implies that MySql never reached 150 simultaneous connections. The per-user Max_user_connections variable is 0, so it should effectively be the same as max_connections. Am I misunderstanding what these variables mean, or is something odd going on with MySql? I use PHP to connect to MySql. The MySql version is 5.7.40 Here are the results of

status like '%connec%';

and

variables like '%connections%';

+-----------------------------------------------+---------------------+
| Variable_name                                 | Value               |
+-----------------------------------------------+---------------------+
| Aborted_connects                              | 776                 |
| Connection_errors_accept                      | 0                   |
| Connection_errors_internal                    | 0                   |
| Connection_errors_max_connections             | 0                   |
| Connection_errors_peer_address                | 0                   |
| Connection_errors_select                      | 0                   |
| Connection_errors_tcpwrap                     | 0                   |
| Connections                                   | 8899838             |
| Locked_connects                               | 0                   |
| Max_used_connections                          | 41                  |
| Max_used_connections_time                     | 2022-10-25 13:57:07 |
| Performance_schema_session_connect_attrs_lost | 0                   |
| Ssl_client_connects                           | 0                   |
| Ssl_connect_renegotiates                      | 0                   |
| Ssl_finished_connects                         | 0                   |
| Threads_connected                             | 1                   |
+-----------------------------------------------+---------------------+

+----------------------+------------+
| Variable_name        | Value      |
+----------------------+------------+
| max_connections      | 150        |
| max_user_connections | 2147483647 |
+----------------------+------------+

Also, I doubt I'm using up all connections by serving web pages; I'm not doing complicated queries, and the data sets are relatively small. Can someone point me to how to find what process/user maxes out these resources?