"Endless" sending messages in Viber?

Question

Viber

After sending a message in Viber, the message itself is marked as being sent (clock icon), but not marked as sent (one tick) or received (two ticks).

Then we have two results:
a). The message was sent, but after a day, or even more
b). The message was not sent and never will be.

The program was repeatedly reinstalled in an attempt to fix it, contacted the support service (which, by the way, works disgustingly), but to no avail.
Device - Xiaomi Redmi Note 8A , if it matters.
Has anyone experienced this or can suggest a possible solution?
Thanks in advance for your responsiveness!