ESP8266 keeps resetting issue

[Min]

I have a remote monitor device using ESP8266 (SDK version: RTOS 2.0). Currently, some of them have a resetting issue after running 2-7 minutes and sending 3-4 messages to the server.
I have tried to get some resetting info by using system_get_rst_info() and send them to the server.
The reset reason is 2 (fatal exception), epc1 are all the same.
Can anyone tell me more details about the meaning of epc1, epc2, epc3, excvaddr, depc, rtn_addr? And how to find the resetting reason?
In the info, the ep1 are the same, but ep3 are different. Why is that?

reason. exccause. epc1. epc2. epc3. excvaddr. depc. rtn_addr
2. 0. 4010762A. 0. 402A6237. 402B2FE8. 0. 402BBA7
2. 0. 4010762A. 0. 402A68FB. 402B2FE8. 0. 402BBA7E
2 .0. 4010762A. 0. 4028C89C. 40285F3C. 0. 402BBA7E
2 .0. 4010762A. 0. 402A1866. 40285F3C. 0. 402BBA7E
2 .0. 4010762A. 0. 402A69FB. 40285F3C. 0. 402BBA7E
2 .0. 4010762A. 0. 40101AEC. 402B2FE8. 0. 402BBA7E
2 .0. 4010762A. 0. 402A69D8. 40285F3C. 0. 402BBA7E
2 .0. 4010762A. 0. 402A69CC. 40285F3C. 0. 402BBA7E
2 .0. 4010762A. 0. 40100615. 402B2FE8. 0. 402BBA7E
2 .0. 4010762A. 0. 402A109C. 402B2FE8. 0. 402BBA7E

I checked the *.s file, at the epc1 address it is

401075ec <__modsi3>:
401075ec: 027d mov.n a7, a2
401075ee: 602120 abs a2, a2
401075f1: 603130 abs a3, a3
401075f4: 3023b6 bltui a3, 2, 40107628 <__modsi3+0x3c>
401075f7: 40f250 nsau a5, a2
401075fa: 40f340 nsau a4, a3
401075fd: 17b547 bgeu a5, a4, 40107618 <__modsi3+0x2c>
40107600: c04450 sub a4, a4, a5
40107603: 401400 ssl a4
40107606: a13300 sll a3, a3
40107609: 023237 bltu a2, a3, 4010760f <__modsi3+0x23>
4010760c: c02230 sub a2, a2, a3
4010760f: 413130 srli a3, a3, 1
40107612: ffc442 addi a4, a4, -1
40107615: ff0456 bnez a4, 40107609 <__modsi3+0x1d>
40107618: 023237 bltu a2, a3, 4010761e <__modsi3+0x32>
4010761b: c02230 sub a2, a2, a3
4010761e: 0027d6 bgez a7, 40107624 <__modsi3+0x38>
40107621: 602020 neg a2, a2
40107624: f00d ret.n
40107626: cc0000 excw
40107629: 000053 excw
4010762c: 494400 excw
4010762f: 0c3056 bnez a0, 401076f6 <_etext+0x7e>
40107632: f00d02 l8ui a0, a13, 240
40107635: 000000 ill

Many thanks!

[Her Mary]

Maybe you can have a try with the latest RTOS 3.4 and its http examples. https://github.com/espressif/ESP8266_RT ... /protocols